Yes they DO work. I have the Cyclecats also. I Highsided my Monser on the track and between the Frame Sliders and the Cyclecat rearsets there was very little damage to the bike and minimal damage to the Cycl Cat stuff.
One things for sure, If you don't have them, they do nothing. I'd say the're cheap insuance. Just don't by some crap, clear acrylic thing with LEDs in them, and think they'll save your a$$.
There is alot of junk on the market. My Cycle Cats were well under $150, and installed in 15 minutes including a beer break!(I always have those with my Monster)
I got my Cycle Cat DS-9s and they really paid off when my bike fell over on a lateral slope. No damage to the bike and the sliders, just some small scratches. $155 worth of insurance....well worth the price.
I seriously doubt that frame sliders would have prevented any of the damage to my bike during my tank slapper/getoff three weeks ago. I was going between 40 and 50 mph and the bike did some sliding with the wheels in the air. The frame is bent at the back from an impact, but there is not a single scratch anywhere on the main part of the frame or anywhere on tha engine.
Frame sliders seem to help if the Monster tips over at walking speeds or less, but don't expect much from them if you go down at a faster speed.
I believe the better ones are designed to break away at some point of stress so the help they offer is good to a point. In Scott's case I think he was headed to hell in a handcart.... his bike could have been bristling with frame sliders and it wouldn't have made a lot of difference
Frame Sliders are great for low sides. I have seen my share of people low side at the track events I shoot. I would not have a bike without frame sliders. I have seen to many bikes saved by them. If you comebine frame sliders and solid mounted pegs, you should be in good shape for your average low side.