After having done a pretty good test (posted here) and then reading the issues of others, it's quite clear that there is a problem. It's not simply an issue of the way people are programming (an accusation I've seen while searching on this issue).
When I ran the test, I used the exact same commands with both the keyboard object and the 360 controller object, starting with the controller object. The keyboard object responded to all of them correctly, the 360 controller object responded to only a few and even switched operations around to other parts of the controller. I'd tell the left thumb stick to command a jump, and it would make the right thumbstick do it... screwy stuff like that. Certain buttons just didn't operate no matter what I did.
Personally, my 360 controller works fine on every game I have. Never had a single problem. It also works fine for me in XNA (I program in C# sometimes) and MMF, but in Construct it's a no-go.