I've been very pleased with my Viper RTX SE. Suspension and handling are great, steers light, - checks pretty much all of my boxes overall. Yes, power is down a bit from the Nytro, but the pros seem to outweigh any of the cons. The fit/finish isn't nearly as good as an Apex. But I would say it is on-par with the Nytro.
Having come from a Nytro RTX, I think back of all the things that I used to complain about on the Nytro:
- heavy steering even with a Skinz front end
- cheap stock gauge
- seating too low
- poor shock valving
- ice build-up in the tunnel
- crappy handwarmers & querky warmer controls
- cold ride
- failing exhaust donuts
- premature wear on a-arm bushing
- bent subframe
- small gas tank
I'm sure I could list more, and all of those items can be fixed/improved - most of which can be found here on TY. But when you compare that to the list of items I have done on my Viper, I've really only done cosmetic things to it. Yes, I'm working on the power/clutching as many others are. But if you are OK with stock clutching/power, then you can check that off your list.
As others have said, it comes down to what you really want in a sled. I loved my Nytro - just had gripes about it that could eventually turn it into a great sled. But the Viper in itself pretty much fixes all my gripes.