I'd rate him with Tana Umaga as the best centre from 2000-2009.
Best player of the decade? No. I'd pick McCaw and Carter above him (even if I am a Kiwi, I genuinely believe it).
Best player ever? No.
Best Irish Player Ever? Probably.
My disliked player of all time: Very close.
For scoring try's Carter can't touch the OD, no way near. Different type of players one a kicking machine, the other a try scoring machine.
As for OD well,
Best centre of all time, his is up there.
Best Irish centre of all time, I think he is.
Best player of the decade, tough debate lots of great players lot's of specialist positions.
Best player ever as above but I would say no.
His records speak for themselves.
Try scoring machine? He's scored 46 test tries in 123 tests...To put that in perspective:
Christian Cullen: 46 test tries in 58 tests
Rokocoko: 46 test tries in 68 tests
Doug Howlett: 49 test tries in 62 tests
Shane Williams: 58 test tries in 88 tests
Jeff Wilson: 44 test tries in 60 tests
Jonah Lomu: 37 test tries in 63 tests
Tana Umaga: 36 test tries in 74 tests
David Campese: 64 test tries in 101 tests
As you can see, he has a considerably poorer record than any of them. The reason why he has so many tries is because he's played in more tests than anyone on earth barring George Gregan. Interestingly, Daniel Carter has score more test tries than any other 1st 5/8th in history, on top of scoring the most about of points. Daniel Carter has scored 29 test tries in 85 tests (.3418) and Brian O'Driscoll has scored 45 test tries in 123 tests (0.3658) so as you can see, there is virtually no difference between the two's try averages.