I've always been happy with the power of the iMacs, personally, so I guess it depends on what you do (although that's still no reason to superciliously dismiss iMacs as Fisher Price toys), but I read the reason the Mac Pro has gone so long it may as well have died completely is that there hasn't been an appropriate upgrade to the chip family it uses that would warrant a redesign?
But then like I say I don't even know what people use them for (that's not a criticism, I genuinely don't know how they are used and what they are needed for) so I don't know how valid a reason that is.
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