The biggest issue with it is the "reversal bug".
They released a firmware just before christmas that greatly improved the accuracy of the X/Y axes of the stick itself:
http://forums.logitech.com/t5/PC-Gaming/G940-firmware-1-42-is-now-available/td-p/542496but afterwords they said there are no plans to fix this bug that exists in all of the other axes, and it has now been a couple months before anyone has heard anything about it. They also mentioned that the engineers and the "powers-that-be" (which I take to mean the executives) call it "hysteresis", claiming it to be more of an improvement than a bug and as a result see no reason to fix what isn't broken.
What happens is if you move an axis in one direction, everything is fine (and precise) but if you stop and reverse its direction then nothing happens for an amount of movement, and then it 'jumps', like it's making up for that deadzone.
Example: You're increasing your throttle slowly... it reads 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31% just like it should. You decide to reverse your throttle back down slowly.. and as you move it you get this: 31%, 31%, 31%, 31%, 31%, 26%, 25%, 24%. Do you see that jump? This makes it extremely difficult to get a precise setting. While with the throttles it's not such a big deal, but with the trims (if you use manual trims) and also the rudder.. it's a HUGE deal. And the amount of this can sometimes exceed 5%! This used to be about 2% on the X/Y stick axes but with the latest firmware they've got it down to about 0.2% and while you can still see it if you try really hard, it's not an issue so much in the stick anymore. This bug used to make flying below 65 feet without autopilot almost impossible!
For normal flying.. yeah it's not a big deal and hardly noticeable... but when trying to get the nose on a tank while strafing it... or while trying to get the trim set correctly.. and while trying to maintain a certain throttle setting during formation flying... well then it sticks out like a sore thumb. This is the kind of thing that a 14 year old wouldn't be likely to notice, but a flight sim enthusiast would, and the enthusiasts are the people who they marketing this $300 piece of hardware to. Now it's like they just want to ignore the problem and hope it goes away.
The reason I'm so passionate about it is that the stick is great! It really is! It's a great value.. the force feedback is pretty incredible. It's held up to almost a year's worth of abuse by me so far with almost no issues (I had to reroute a wire in my throttle due to a bug that would stretch it out when moving the throttle up and cause the throttle trims to spike but it's a 30 second fix). If it was a piece of junk I'd simply have sold it or thrown it away but it is pretty nice. If Logitech could just get their heads out of their... well you know... and stand behind their product and listen to what their customers have to say (instead of their engineers) it could easily be the best stick out there.
Next month when my warranty is up, I'm going to purchase one of those
joystick controller boards and wire my throttle and pedals through it instead. The Logitech stick can function on its own so by doing this I'll only have the 'reversal bug' on my stick's trim knobs and its mini-stick but it will cure my throttle and rudder issues. The only drawback is that the throttle buttons will no longer be programmable but no biggie.
When I do this project, I'll be sure to take many pictures and post the procedure here.. in english!