So my very first rep watch purchase was going to be a TAG. I admire the Calibre 17 model with its excellent symmetry and beautiful design. As this was my first rep, I wasn't sure if I should stick to a true asian mechanical movement or give the new Seiko VK quartz a try. I decided to buy both and do a comparison for everyone. Full disclosure, I do greatly prefer mechanical movements over quartz.
For those new like I was, here's a few things you should know before deciding:
In this picture, you can see them side by side with quartz on the left and mechanical on right. First thing you'll notice is the different sizes. For some reason the quartz version is larger. Lookup up the advertized size of the original says it should be a diameter of about 43mm. The quartz is a huge 47mm while the other is 43.5mm. I'm not sure why the quartz is so big, but personally, I ended up liking the larger size. It stood out more and brings more attention, but obviously isn't like the original.
Both appear to have a sapphire crystal but the mechanical one seems like it's a much thicker crystal. The quartz version doesn't have the same sound when I tap it which could be from the thickness difference, but likely is not sapphire or has a thin layer of sapphire or something. With a smaller diameter and thicker crystal I assume the mechanical one will survive a good hit where the quartz may crack. Who knows!
The quartz version has a larger gap around the outer edge of the dial than the original and there are other minor differences. A few obvious ones are that it's missing the word "Automatic" on the dial and the hour and minute hands do not appear to reach out as far because the edge is farther away. The numbers around the dial look good and overall it's not bad in my opinion.
The quartz one doesn't fully mimic the original in function. The tachymetre start/stop works but has a slower tick movement instead of the smoother mechanical version. The tick isn't as bad as a standard quartz, but you can tell something is up. The reset button works as it should. The right dial at 3 o'clock is not a seconds hand like the original, it is a functional 24 hour indicator. The left dial at 9 o'clock doesn't do anything. The date indicator at the bottom works as it should.
The mechanical version looks very close to the original dial. The tach (large seconds hand) works very well and is relatively smooth. Putting this to my ear I can tell it is a 21,600 BPH movement which surprises me as I thought most of the A7750 models were 28,800, but not this one.
Everything works just like the original with the right dial acting as your seconds dial and the left dial is only used when the tachymetre is started to track minutes. The seconds dial at 3 o'clock is not a smooth movement, it ticks, which from what I've seen in videos of the original, appears to be accurate.
Obviously you can see a difference here. 
The quartz version has a solid back with fewer screws and the mechanical version has the proper windows. The wording on the quartz is easier to see
but the mechanical looks just like the original. Even the weight inside has the correct TAG branding on it. The mechanical one does bulge out a bit more on the back than the original.
The crown and buttons appear similar but none the buttons or the crown will screw down on the quartz version, so it is very likely not going to keep any sort of water out. The mechanical one fully screws down as it should, but I have no idea how water tight it is and I don't plan to test it.
The bands are not the same quality. The band with the quartz is obviously cheaper with larger gaps between the links, and the clasp when closed is a little crooked, but the links do feel individually solid, but seem really loose when connected to each other. The mechanical version has a tight band that aligns perfectly and just feels like a higher quality band overall.
So in summary, I do like the larger look of the quartz version, but everything else with the mechanical version is a winner in my book.
The obvious question is, what's the price difference? Significant is the answer! The quartz model is only $190 while the mechanical is about $350. If you are looking for a nice watch and don't mind the quartz or the differences, then you can't go wrong with the quartz for that price. If you want to convince people you got an original, then go with the mechanical version.
The only outstanding question is how long will the seconds at 3 survive?
Hope this comparison was useful and I apologize if I didn't use all the proper terminology as I'm quite new in this hobby.
For those new like I was, here's a few things you should know before deciding:
- The Asian 7750 movement appears to be a decent substitute for the real thing, but the seconds gear is always at the 9 o'clock postition on the movement. This TAG model however has the seconds movement on the oposite side at 3 o'clock. This is considered risky as they typically do not use jewels with the gears that take that movement to the 3 o'clock position and so this part may fail one day and possibly take out the whole watch.
- The Seiko VK movement is quartz, so it is extremely accurate and should last longer than the A7750 movement in theory.
In this picture, you can see them side by side with quartz on the left and mechanical on right. First thing you'll notice is the different sizes. For some reason the quartz version is larger. Lookup up the advertized size of the original says it should be a diameter of about 43mm. The quartz is a huge 47mm while the other is 43.5mm. I'm not sure why the quartz is so big, but personally, I ended up liking the larger size. It stood out more and brings more attention, but obviously isn't like the original.Both appear to have a sapphire crystal but the mechanical one seems like it's a much thicker crystal. The quartz version doesn't have the same sound when I tap it which could be from the thickness difference, but likely is not sapphire or has a thin layer of sapphire or something. With a smaller diameter and thicker crystal I assume the mechanical one will survive a good hit where the quartz may crack. Who knows!
The quartz version has a larger gap around the outer edge of the dial than the original and there are other minor differences. A few obvious ones are that it's missing the word "Automatic" on the dial and the hour and minute hands do not appear to reach out as far because the edge is farther away. The numbers around the dial look good and overall it's not bad in my opinion.The quartz one doesn't fully mimic the original in function. The tachymetre start/stop works but has a slower tick movement instead of the smoother mechanical version. The tick isn't as bad as a standard quartz, but you can tell something is up. The reset button works as it should. The right dial at 3 o'clock is not a seconds hand like the original, it is a functional 24 hour indicator. The left dial at 9 o'clock doesn't do anything. The date indicator at the bottom works as it should.
The mechanical version looks very close to the original dial. The tach (large seconds hand) works very well and is relatively smooth. Putting this to my ear I can tell it is a 21,600 BPH movement which surprises me as I thought most of the A7750 models were 28,800, but not this one.Everything works just like the original with the right dial acting as your seconds dial and the left dial is only used when the tachymetre is started to track minutes. The seconds dial at 3 o'clock is not a smooth movement, it ticks, which from what I've seen in videos of the original, appears to be accurate.
Obviously you can see a difference here. The quartz version has a solid back with fewer screws and the mechanical version has the proper windows. The wording on the quartz is easier to seebut the mechanical looks just like the original. Even the weight inside has the correct TAG branding on it. The mechanical one does bulge out a bit more on the back than the original.
The crown and buttons appear similar but none the buttons or the crown will screw down on the quartz version, so it is very likely not going to keep any sort of water out. The mechanical one fully screws down as it should, but I have no idea how water tight it is and I don't plan to test it.
The bands are not the same quality. The band with the quartz is obviously cheaper with larger gaps between the links, and the clasp when closed is a little crooked, but the links do feel individually solid, but seem really loose when connected to each other. The mechanical version has a tight band that aligns perfectly and just feels like a higher quality band overall.So in summary, I do like the larger look of the quartz version, but everything else with the mechanical version is a winner in my book.
The obvious question is, what's the price difference? Significant is the answer! The quartz model is only $190 while the mechanical is about $350. If you are looking for a nice watch and don't mind the quartz or the differences, then you can't go wrong with the quartz for that price. If you want to convince people you got an original, then go with the mechanical version.
The only outstanding question is how long will the seconds at 3 survive?
Hope this comparison was useful and I apologize if I didn't use all the proper terminology as I'm quite new in this hobby.