i've run co2's for years,good grip in mud,rocks etc and last 3-4 times longer than fim enduro tyres i've used so good value for money.i've averaged around 1,600 miles on a rear compared to 4-500 on mich comp3's before they're no good in the soft stuff.the c19 or ef06 fronts aren't to bad either but the wear rate is that similar to any other available fronts
only problem you may encounter is due to the high aspect ratio you may find that the tyre comes into contact with the shock protector,worth bearing in mind if your chain is relatively new/unstretched.i usually run an extra link to compensate.
i do find them a little sketchy on damp roads when brand new but a hundred miles or so and they're no worse than any othr knobbly imo.the only other thing i can say about them is they do'nt like being ridden on when you have a puncture,i've had a couple of them where the side wall has broken up when i've ridden with a flat just to get me the last few miles home or back to the van so a repair is req(it was just me being lazy!
)
hope this helps
Steve