Quote G1="G1"If we want to discuss the respective merits IMO its' easily Diskin.'"
It's an interesting one. I'd suggest the only way Diskin has bettered Roby in the last few years is by playing for Leeds and picking up the GF as a result.
For example, in the same number of appearances last year, Roby had:
Same number of tries
Same number of assists
Almost twice as many metres (2548 v 1368)
Over 100 more carries (367 v 253)
Over 100 more tackles (723 v 600)
More offloads
Same number of attacking kicks
More runs from dummy half
More tackle busts
Almost twice as many marker tackles
Over double the clean breaks (8 v 3)
More forty twenties
More kicks in general play
Far fewer missed tackles (despite making far more)
The only stat Diskin comes out on top is that he gives fewer penalties away.
I'd say that's far from clear (ignoring the fact Roby is preferred at international level too).
That's not to say Diskin is a poor player, he's a very good hooker indeed. But I think people talk down Roby now that he doesn't score as many tries and ignore all the tremendous work he does for Saints.