Best: Dualshocks from Sony. They've remained relatively unchanged over the consoles, but I think that points to the quality of the controller (what ain't broke, don't fix, right?). I know part of my love for the controller has to do with owning all the Sony systems and having become accustomed to how they work, but I do find them to be great controllers regardless. Very light to hold. And the symmetry is tight. Six-axis on the PS3 is a little annoying, but I personally don't own any games that utilize the technology, so it's not a bummer (but, does point to its uselessness).
Worst: Kinect. I know that technically it's the first-gen controller of its kind, so it's allowed to have some faults, but it's definitely not a good show of what this technology has to offer. The space needed to play Kinect properly is ridiculous. It was clearly intended for shorter people. I'm on the taller side, and for Kinect to see me properly, I had to stand almost 12 feet away from the sensor, which had me moving a sofa out of the way to get far back enough. Going through that every time is too much of a hassle: why bother when when you could press "ON" and play normally with a handheld controller. There are other issues -- the fact that Kinect has trouble tracking movement properly, and has even more trouble with the tracking when two people are playing together, Kinect isn't always listening when you speak to him/her, the list could go on. Basically, it's at the bottom of the controller pool right now. Especially considering that Dance Central, one of the titles on it, is hella-fun, but can get really irritating to play for the above issues. But, I'm not planning to buy one myself (entry cost is too much for me), that's just my experience with it.