I use a Saitek X52 (not pro). I actually have two of these sticks, I've been extremely happy with them. Fully programmable with external software. My two favorite features are the MFD with programmable time zones (which really helps me figure out server times related to my own and when events are kicking off online) and the thumb mouse/button on the stick, which lets me navigate menus when necessary without taking my hands off the stick.
I have four negative things to say about this, however:
1) It is much better to program the Saitek sticks in the given game engine then to do it with the programmable software. There is a microsecond delay when you hit a button and the software has to interpret that to match a keyboard command. This is a real problem for two reasons. First, a microsecond delay when popping chaff to save your life means your dead. Second, many games don't allow you to map all your joystick buttons to the in game functions, or only allow a limited mapping. This is less likely to be a problem in Star citizen.
2) The spring in my X52 does not offer as much resistance as I would like. I have considered replacing it, but this would mean disassembling the stick, something I have no interest in doing. This is really personal preference - I have always used sticks with extremely tight resistance and it was an adjustment to what I have now. This is something to consider but may really depend on what sticks you have used in the past. I got my start with a Microsoft Sidewinder, and it snaps back into center position like a champ. This stick...not so much. The pro may be different, I don't know.
3A) This is really a comment on the sad state of video games, but a lot of the games I play - especially the older ones - don't recognize the Z-axis. This means no twist. This games typically don't recognize the rudder pedals either.
3B) Point number four, and tied into the above, is that many of the older games also won't recognize the throttle. This can be extremely frustrating.
In addition to all of this equipment, for certain sims I round it out with a matching set of Saitek Rudder pedals. I only purchased the Saitek brand because they already used the same programming software I had installed, so it saved me some additional work. I also have a Track IR 4 that I use with certain sims that really enhances the experience.