"Advanced Running Dynamics," ie, a lot of junk about your ground contact time, vertical oscillation, left/right balance.
Touch screen (finicky, and not really good during activity, but good for setup)
Wifi (actually pretty nice, in that it uploads way, way faster than via bluetooth).
4 fields of data per screen and no limit on the number of screens. (Also more useful than you might think).
Anyway, the 630 is almost 2 years old, and is still pretty expensive. I wouldn't buy it.
I had the same experience with the TomTom watch. The manual lap function was pretty much defective. Fortunately, all the Garmins do manual lap just fine. If cheap is all that matters, then the Forerunner 15 will do, but at that level, I would get a Polar M400. It's a vastly superior watch, and you can get it for just over $100. The only issue with the M400s is that some of them have had issues with corrosion in the micro usb charging port. Just make sure you wear it in the shower after you run (it's the salt, not the water, that causes the problem), and it'll be fine.