Yep, that's pretty much the impression I get too. Which is why I think he'd smack the **** out of Jones.
Greb is one of the few MWs/LHWs with the speed to cope with Jones, and his relentless swarming pressure tactics would be a stylistic nightmare for Roy. Given Greb's granite chin, and moderate power, it's likely to go the distance. I would favour Greb winning by a few rounds in a hard-fought match.
Greb wasn't the fastest in his own time, Bartfield and O'Dowd I read were faster and it's said he had trouble with fighters with faster hands than himself
I dunno about those guys being faster but greb's reflexes would have a lot to do with this fight. Depsite his agrressive style he was very hard to hit cleanly, even Loughran and Tunney couldnt do it, they were master boxers. Greb's reflexes were just as good as Jones, but then again, the best way to beat Greb was body ounchung and Jones was a mean body puncher (hill fight, kelly fight.)