I have the nytro suspension in my 800. It flat out rocks!
I have tried almost all the skids out there, extra 10, 12, sc10, sc3, sc4, zr, fcat skid, proaction, proactive(nytro skid aka dualshock), mono, m10.
And honestly for all around riding, easiness to tune, and durability, the nytro skid is one of my favorites.
It handles the bumps extremely well, transfer is excellent, incredibly simple to adjust transfer and stiffness. And although it is of similar design to the other manufacturers suspensions, it is built much stronger, though with no difference in weight. It took maybe 20 minutes after installing mine to get it tuned the way i like it, and my "big heavy" vmax4 feels so light its almost like im never touching the ground.
They are usually about $700 used, but if you look hard enough, I found mine for $150.
Nytro skid is amazing.