Most of what has been stated is right on, but I am curious as to why you ask? I mean I think this is relative to the watch, you know what I mean?
Obviously a 21J and a clone or ETA 2836 are way different, but have their places in the hierarchy. When it comes to movements, I truly believe you have to have the watch in mind first. I mean the difference between autos, manual winds, and those with chronograph functions very greatly. I wouldn't want a high end movement in my cheap-o rep beater sub necessarily, but I also don't want a 21J in my Franken Sub-C.
So with that said my answer is this, if you want a workhorse in a standard watch with no complications except for maybe a date function, then the ETA and clone 2836 and 2824-2 movements are great and so are the Japanese Miyota movements. The clone and ETA movements are typically high beat and very reliable. And to what TB said, high beat 28800 is the majority of the watch world in terms of high beat movements, so no real need to get something with a higher beat. As for the Miyota movements, they get a bad name because of the rotor noise, but this can be dealt with by oiling the proper parts within the movement. You will find that most all movements (especially in reps) could greatly benefit from a proper service. When it comes to reliability and "smooth" running, servicing the movements might be the most important part of this equation.
If you are looking for chronograph functions, the 7750 (when properly serviced) is a workhorse and gives you auto wind. For manual wind in a chrono the ST-19 seems to be the movement of choice for reliability.
Hope this helps. I am by no means an expert on this, but with the information RWI provides, I have learned a great deal and look to learn even more.