Re: Better overdrive pedal?
For Classic Rock/Blues, with a strat into a Twin reverb...I'd go with neither of those...I haven't tried the Green Rhino, considering it hasn't been released yet...But its basically a modded Tube screamer, with alot more options (the new one at least). Which isn't gonna sound too great, for anything other than light clipping, into a clean amp. Now, the way huge Pork Loin on the other hand, would cover classic rock/blues tones, into a clean amp very nicely. Great, great stand alone Over Drive.
Beyond that, I'd say check out the Zvex Box of Rock (or distortron). Supposed to sound like a Cranked Plexi, in a box. And the three times I've had a chance to try one out, it definitely delivers. The best sounding Marshall in a box I've ever tried. The B'o'R and the Distortron are basically the same thing, cept the BoR has a built in Boost, and the Distortron has a few more tonal options for the distortion. Theres a few guys here who absolutely love theirs, an I'm sure they'll chime in.