I think the critical reason why Apple would not choose the Cell processor was simply that there is not going to be much commercial pressure on the Cell to develop.
Once the PS3 is released, its architecture will remain pretty much the same for its entire product life. The cell is expected to be used by Sony in other consumer products, but almost all of these are products where you generally wouldn't really care what sort of processor it had - things like camcorders and DVD players, for instance.
So, without it being used in an application where there is an ongoing pressure for better and faster processors, its likely that the Cell processor will not be very actively developed.
For Intel, its a very different matter. Their entire business relies on their chips being at the cutting edge of performance. While the Cell *could* sit at its current level for three years without causing Sony any headaches, the Intel architecture has to advance. For this reason alone, I think Apple made the right choice.