So far I like it. It comes in handy if you hit an unexpected climb and it I like having the instant high/low gearing.
The only issue is that the Wilson has a high chainstay on the drive side so chain runs just over, or when into the travel, just on top of the chainstay causing rubbing. As long as you have a chainstay guard, or an innertube (that needs replacing every few rides) you can minimize damage.