Rock Band came out for the PS3 almost a year ago (Nov 20, to be exact). Early reports indicated problems with the instruments malfunctioning or not functioning at all, particularly the guitars. EA offered extended warranties and hassle-free replacements for DOA hardware, and is still offering the same service to this day. What's sad is that a year in, they apparently haven't done anything to remedy the manufacturing defects, faulty QA, or the overall experience. It's kind of like the Xbox 360 hardware problems (though supposedly the Elite model or Jasper chipset may finally address the problem directly).
I was waiting for these fixes to make it into the retail product. Generally that plan works. Wii users had problems with the wrist straps breaking, so not only did Nintendo beef those up, they started putting Wiimote covers in the box. That doubly solved the problem of not only losing your grip, but of the thing flying into the wall and getting destroyed.
EA doesn't seem to get it, and the consumers were still getting screwed out of simply resolving the issue with Guitar Hero controllers due to Activision's stubborn refusal to allow a fix patch to go live until they got their share of EA/Harmonix's profits. However, rather quietly, with the last patch to Rock Band, this has finally changed. Having dealt with two Rock Band Stratocasters that worked like crap, I was ready to try something else.
Along came the Guitar Hero 3 Les Paul guitar controller. It's laid out with minor differences than the standard Rock Band axe, but for the better overall, in my opinion. Mainly, the whammy bar isn't loose and floppy, something that started happening sometime after Guitar Hero 2 came out. Said bar stays right where I put it, just within reach without having to move my whole hand. More importantly, it WORKS.
The main issue we had with the original RB controller was that the tilt sensor only worked for overdrive maybe 10% of the time. On the replacement we got, we couldn't get the tilt sensor to work at ALL, and the fret buttons felt less responsive than our previous one. Thankfully, we did the express replacement method and just sent back the P.O.S. they sent us. I read about people even busting open their guitars here and here to readjust the angle of the tilt sensor, which apparently fixes the problem. I wasn't going to go quite to those lengths and void my warranty. There was talk of different types of switches, from mercury to ball bearings in a tube. Surely EA would have tried something different by now, right? Wrong.
In any case, the Les Paul works just fine with Rock Band after that last patch, more or less. Before you buy anything, though, check the compatibility matrix to be sure. The tilt sensor finally works as it should, with a GH-era level of responsiveness (no more holding it up for a minute and a half for nothing; it activates instantly), but there still seems to be random general timing issues where several notes quickly repeat in succession, regardless of which controller you use. That didn't happen in GH 1, 2, or 3 (on the PS2, at least). It Seems to have started in this age of all wireless controllers. A friend of mine similarly ran into issues with Assassin's Creed where holding down several buttons at once to accomplish a particular move would fail on wireless, but worked fine on a wired controller setup.
In any event, those still struggling with EA and their sub-par Rock Band guitars would do well to pick up the Guitar Hero 3 Les Paul model. Now that they're compatible on PS3, there's really no good reason not to. The missing set of up high solo fret buttons may concern people with tiny hands who used them, but the improved functionality seems well worth the trade off.