Actually M2M is more preferable for someone new.
1. your collection has 0 reps in it, it's only a matter of time before something you'll want will turn up
2. as a newbie you probably won't know what to look for in QC photos, when you buy used at least you can trust the other person to do their due diligence before they bought theirs(well provided you buy from people with decent feedback...since they usually know what they are talking about)
3. you'll save money, and if you get bored of the watch you'll be able to sell it without losing money....so it's like putting a refundable down payment on a watch
4. no risk of customs or anything like that(well provided you buy from CONUS users)
5. it'll keep you from spending too much in a short time. With TDs, you could drop $3K in 1 week of looking through their site. If you stick to M2M you can slowly grow your collection and can actually enjoy each watch, instead of getting 10 watches at the same time and not really appreciating them(plus when you get that many, chances are you'll have one or two favorites, so 8 watches will just be collecting dust in your watch box.