I had nothing but trouble with Harley's POS compensator and tensioner on my FLHXSE, so I installed a BDL cs-34a compensator and the Hayden tensioner on my new Ultra. Unfortunately, I got rear ended before I could put any time on the bike, so I can't yet tell how they'll work over time. My initial impression is similar to what others have reported here: quieter shifting, easier to find neutral, etc.
There's very little info on the 'net, but I think the BDL comp will work well. Couldn't be worse than HD's comp. I got the impression that there was less "clunk" on starting, but since the Ultra was new, it didn't have time to put much wear on the original compensator. I'll report my impressions on the BDL compensator after I get the bike back and ride it for a while.
The biggest improvement for me was putting Redline Shockproof in the tranny.