I've dealt with both, and x52 pro all the way. x55 feels like cheap, bakelite plastic, and I had a couple of the buttons and knobs break on me when I used it for other games. A lot of the stuff seems to be overly themed while nor actually useful.

My x52 pro, on the other hand, is the only thing I've flown 800+ hours of Elite with, and I wouldn't trade it for anything else. The feel is perfect; there's buttons and switches right where you want them, and the thing is durable as hell. I find myself abusing the shit out of that stick in some dogfights; stuff that by all means should and would snap other sticks in half, and yet there's nothing wrong with it aside form a little bit of looseness in the center yaw detent, which I've heard can be fixed.

Speaking of detents, the one thing I would suggest if you buy one is to remove the notched detents in the throttle; they are designed to be programmed for afterburners and/or airbrakes and/or reverse in some other games, but they don't really fit in Elite which has you constantly manipulating the throttle, especially in fa-off. The detent becomes less effective with use as well, and the only thing on the stick that ever gave me trouble was the detent; physically blocking my throttle from going past 90% when it finally wore out. After removing it it works great and has a smooth 0-100 ride, and I wish I had removed it right when I bought it.

The process is extremely simple; just unscrewing the baseplate and taking out a rubber notch with some pliers (or your fingers but it's covered in atomic super lube); and it can be re-inserted easily if you want it back.

Here is a nice tutorial -http://forums.eagle.ru/showthread.php?t=67680