The ProActive CK skid in the 07/08 RTX is much more durable than the Monoshock in the 06 RTX.
Last season I rode the same trails at the same speeds as my buddy on his 06 Apex ER. At the start of the season he had a brand new, complete skid installed by Yamaha due to number of pivot arm and slide rail failures he had the first season.
During his second season he went through two front pivot arms, one pair of slide rails and one rear pivot arm. My 07 RTX has just now got a small crank starting where the optional Yamaha idler wheels mount (cantilevered without any reinforcement like the original monoshock inner idlers) and the limiter straps both broke this season. Without those idlers, I'm sure my rails would still be fine too.
We ride hard, but we also ride with a bunch of REVs and now REV-XPs. We don't ride hard enough to break the REV skids ever, but those Monoshock skids can't handle our aggressive riding at all. The 07/08 RTX (so far), seems to be on par with the REV for skid durability. If my skid starts to break now (I hope not), it is still far more durable than the monoshock.
As far as comfort and performance, the Monoshock is definitely better at soaking up stutter bumps. As shipped, the 07 RTX has no where near enough rebound damping on the center shock, nor anywhere near enough high speed compression damping on the center nor main shock. For a rough trail sled, it does provide a rough ride, but it also bottoms out very easily.
I'm now running new custom valve stacks from Carver Performance in these two shocks and my 07 RTX is now an awesome performing rough trail sled. It is extremely difficult to bottom out now but the biggest improvement I found is it is now very stable at high speeds on rough trails. I'm going to write up and post a review about the Carver shock calibration.
