Been really happy with my Reverb so far. Bought it cheap from Wiggle and it was easy to install, easy to shorten the hose, easy to bleed, very in action and not much play in it. I like the ergonomics of the lever too especially when run under the bar out of the way. I run a 1x10 set up so I use a right hand lever under the left side of my bars where it is mostly out of harm's way.
My only complaint would be that spares are expensive.
I have used a Lev on a demo bike and it was pretty good. I didn't like the lever being integrated with the grip though because it felt too close to my thumb to use comfortably. Nice idea though. It also had slightly more Olay in it than my Reverb and I didn't think that the action was quite as smooth. My big issue with the KS posts is tveacj of UK distributor. No dropper post is immune to failing so I felt happier having UK support than having to ship it off to Europe somewhere.