Hi Josh, as far as the engines go I have had both. I've sold, serviced, and ridden, the 2-strokes for over 10 years. With that as background I can tell you that when I got my first 4-strokes in '05 I quit riding the 2-strokes altogether. I now only ride them as part of building, repairing or testing.
The 4-strokes are smother, cleaner, more powerful, last longer, and are over-all better built in every way. Due to the history of the Chinese 2-stroke kit engine, I can tell you that every nut bolt and screw in the HS 4-stroke is a higher grade than the in-frame 2-stroke. There are much better 2-strokes made, but not used in frame yet.
Due to smoother running, and better quality, most of the 4-stroke owners find that if they built their bikes well, that they can ride them more, instead of spending so much time maintaining the bike. They are also much more fun to ride, IMHO.
If you get a chance, do try both, but know this, the 4-stroke is generally cleaner, smoother, and will last MUCH longer. Your investment, IF you get a good Drive, will far outlast the cheaper some-times short-lived 2 stroke in frame kit.
Mike