This thing originally listed for something like $200, which is ridiculous. At the price I paid-- around $75-- it's worth picking up.
It's got soft (but not mushy) buttons and a smooth neck that makes sliding your hand/fingers around effortless. The strum bar doesn't click loudly like the classic Guitar Hero controllers, but there is some slight aural and tactile feedback, unlike the completely smooth/silent Rock Band guitar strum bar.
And the thing is built like a tank. Solid wood neck, and (I think) an aluminum body. It has the weight and feel of an actual small electric guitar.
It's wireless, with a USB dongle that works for the PS2 and PS3.
I've been using it for a few months now, maybe 10-15 hours per week, and it still works like new. Still using the original set of included AA batteries, too!
If it does end up breaking, though, I'll definitely buy another.