Never run a dropper post in the past on my bikes, but I am starting to think I want to try one out, finally. The only experience I have with them is sending ones out for warranty or getting parts in for them when they broke, so I only know the bad. School me on the good and what you guys/gals like about the ones you have. 

Its going on my 29er hardtail to make it a little more friendly on the longer downhills when I go to Pisgah/Boone/Wilkes since I am tired of getting tagged in the gooch from time to time. 

30.9
100-125mm travel

I know the KS models seem to like to rattle where the saddle attaches, the CommandPosts don't like to be slammed up or down which breaks the collets over time, seen a few leaky Reverb's and don't have any experience with the Thomsons. 

I have experience with the KS lev and the reverb. The lev works great when the cable is adjusted perfectly, but that seems to always require fiddling, once a month or so. It's never totally failed on me, but it also hasn't been a 'set-and-forget' experience. I do like how the cable-post joint is on the stationary part of the post, so it doesn't go up and down during operation. There is no rebuild kit for sale by KS, and it sounds like quite a long turnaround time to send it in for service.

The reverb feels very smooth, and stays that way for longer. When a problem does pop up with the reverb, rebuilding it is quite easy. They sell 2 rebuild kits, a $8 one that has the main o-rings and a $50 one that has pretty much every wear item in the post. If you're willing to do some work on it every year, I'd say the reverb is a clear winner. It's definitely the one I would buy again.