Yes, the J Skis are good quality. They are just a very specific type of ski, whereas other companies have much wider offerings. I'm positive that this will change over time.
To answer the original question, today I went out and rode the Prester, which is the closest thing in their lineup to what J Skis is doing.
The Prester was definitely badass, but very different than the Newschoolers J Ski. It was cambered, stiff and built for hitting massive jumps, super pipes and charging super fast. I absolutely loved it, and it had dramatically better edge grip than the J ski I was riding.
I'd sum it up by saying that if you go with ON3P, you get a company that builds a stiffer ski, and has a bunch of different offerings of creative shapes and styles of skiing. The Filthy Rich is a very cool park ski using crazy rocker and an interesting shape. The Prester is a burly cambered park ski for the big stuff. J Skis you get really cool graphics, and a ski that is very soft, springy and playful. The wider one they offer likely would have the same characteristics - though I have not tested this - and would be a whole pile of fun.
You should try a rockered ski, as its an interesting experience. They are a lot better when you get stuck in some snow with your park skis, though personally I still really like a more traditional cambered soft ski when playing around in the park.
"I don't really count a trick until i land it CLEAN or with a grab. do this and you will get pussy."
Check out what I ride these days here - http://bit.ly/19DCx96