Both are indescribably brilliant. I think I'll hand it to the Clash for more output, lyrics and musical genius. Anything to do with Joe Strummer will be brilliant, most definitely.
The Clash never did any such thing as sell out, they released an album that was awful, but still a root dug in punk. It was called "Cut the Crap", and it was hardly the Clash. It only had half of the classic lineup in it, and the band have since disowned it. And it was the opposite of commercial, it was the most uncommercially independent record released on a major label. Strummer was in an emotional rut whilst recording it, and only part half his will into it, yet still was able to come up with the classic "This Is England". And if it was "Combat Rock" you were referring to, this was when The Clash was at their most commercially and record label revolting, and were the only band who were more than reluctant not to sell out. Just because it was the record of one of their most commercially successful songs means nothing.