I had the X-45 and recently upgraded to the X-52.
Differences;
X-45 has a rudder rocker under the throttle quad on the left side. Rudder on the X-52 is a twist joystick style control. (I liked the one on the 45).
The buttons on the 52 are incredible! But somewhat different then the 45. more buttons on the 52.
The 52 is far more 'subtle' then the 45 with much more softer control able to be done. The 45 wasnt as nice.
The 52 has odd 'lock zones' in the throttle, where as the 45 didnt. Full on, to full off. The 52 somehow has a reverse prop zone at the back (towards you). At first, its difficult to get used to.
The 52 has an 'auto-calibrate' software system in it. You 'can not' calibrate it. You 'must' restart the computer to run calibration. This is rare though. (I found out about this as I was flying in a slow circle and coudnt figure out how to calibrate the darn thing. Found out its automated on bootup. The 45 has a calibration center, so thats another factor).
The blue lights on the 52 are very bright (I think) and there are MANY of them, lol... . So if all the light bothers you, you will need to pull the USB plug on it, like at night. I plug it in only when I am going to fly, so my lights to not wear out.
I am happy with the 52 aside from calibration, throttle rear lock, and the twist rudder control. I kind of liked it on the left side and for it to be a rocker, which sort of reminded me of a rudder bar on the floor, for some strange reason, lol..
Great joystick sets! I think they are the best...
Bill