Yeah, I've always wondered about overdrive pedals myself. I've got such terrific distortion from any of my three Mesa heads, I never felt the need for one. But the even greater concern, is that there are so many to choose from! Try buying a few unsatisfactory, unreturnable boutique pedals, and you quickly could have just purchased a whole other amp instead!
So, I'm more gunshy, than "against" the concept of a pedal in front of my amp. I once got a Fab Metal pedal for free, and as lame as it is, it sure is FUN! (Not against effects either. I have a TC Electronic G•Major, but I have that inserted AFTER my mic preamps.) So, I'm quite sure there's something to be "gained" here. So, the OD pedals I seem to see most highly recommended are:
1. Fulltone OCD.
2. BB preamp.
3. Tubescreamer (which one???)
I really like how my LP Studio sounds in comparison to my DiMarzio-equipped HM Strat, straight into my amps, so I was going to pick up one of those Seymour Duncan pick-up boosters. It's supposed to just send a hotter pick-up signal to your amp, which I like.
Oh yeah . . . I'm only interested in metal, lead-channel kinda sounds. Don't need cleans or "blues-ey overdrive" sounds at all. I know, everyone has their biases, but any advice and further discusson is most welcome!