Clapton (on Beano, anyway) sounded a lot more studied, respectful, and reserved, to me. Green's playing sounded like there was nothing, no theory, no attempts at "authenticity," no imitations of somebody else's "thing," no Peter Green, even, between his raw emotions and those strings.
It wouldn't have even mattered if Green had played some other instrument, instead; that's the kind of {censored} that's just got to fight its way out, somehow.
Clapton impresses the hell out of me.
Peter Green scares the hell out of me.
I agree about the studied part, but actually, I always thought EC came across as the more agressive of the two *IF* you compare Beano with Fleetwood Mac or Mayall era Green.
I also hear a lot of tradition in PG's playing - different influences from EC and a different approach to them, but to my ear there's no doubt Green did as much and as deep listening as Clapton.
Of course, at the end of the day they were both outstanding in their way