I used the G940 for about a year and had a good experience with it. I didn't use FSX force feedback - instead, as recommended by a number of other simmers, I paid a little extra for
FS Force, which gives you much more accurate stick forces and a number of good (tweakable) profiles. This "
Heavy Prop" profile is a blast with the A2A B-17 and the Aerosoft Catalina, among others. There's also a good profile that Bill Womack developed for the Piper J-3 Cub, available
here (along with a good writeup on FS Force itself).
I never used the Logitech profiler - I handled all the axes and assignments either through FSX or through FSUIPC. Had no problems with either method.
Mine died for unexplained reasons a few months ago. At the time I was considering going over to a yoke anyway, so I used that as an excuse. However, I couldn't get a yoke to give me enough precision (was using CH and Saitek, not the heavy gear like PFC), and eventually I shelled out fairly large bucks for the Thrustmaster A-10 Warthog HOTAS. Have never looked back. The degress of control made possible by the Hall Sensors (magnetic, not mechanical) is like nothing I've ever experienced. And the stick is so good, I don't really mind the fact that I'm missing force feedback.
My advice is, if you're considering a big investment in a controller, take a good look at the Warthog. It's costlier than the G940 but it pays you back in quality. If you do want to go with the G940, FS Force is a must.
Let us know how you come out.
Best,
Alan