They are all competitive. Just take everything you read with a grain of your favourite condiment and pick the one you think looks the best. What one person raves about the next guy is meh. It's got a lot to do with (1) driver (2) setup (3) flavour of the day. For example, I think the RB6 is the best and the rest is all rubbish. Except the Schu KR. That one is pretty.
Between those two, I'd pick the Serpent. I had a dex210 on release and it was nice and reasonably easy to work on, but sometimes seemed to strike me as a bit overcomplex. Use 2 parts to accomplish what other buggies did with one. The front lift up thingy is an example of that. Nice idea. Not entirely sure what the point was.