You can't really compare them, they are for different things, a Cell behaves a lot more like a GPU, if that makes any sense.

So like people mentioned early why doesn't Sony eliminate the GPU and put two Cell processors in the PS4 like they originally were going to do? Surely the Cell is cheaper now to get good benifits out of it.

A cell does not behave like a GPU at all, if that makes more sense to you...

When the idea of using two cells in the PS3 was laid out, your typical GPU was a pretty "weak" thing, it had a very few shader groups running at a few hundred MHz at best. So using a 8-core SPU chip at several GHz was "a lot faster" than any existing GPU, a t least on paper (and apparently they tried and couldn't get it to perform reasonably for whatever reasons - hence the GT7800 GPU tacked into the PS3 in the end). Times have changed since. Even a basically mid-range APU like the A10 has a GPU with almost 100 shader groups, running close to 1GHz. You can't stuff so many SPUs in a cell to compete with that nowadays.

The correct path to the PS4 would have been an improved cell chip, 3 enhanced PPUs and 4-6 enhanced SPUs (no need for more SPUs, as the GPU now does the graphics stuff) at 28/32nm (basically leading to a 150mm^2 chip, not much bigger than the cell chip now), and a modern powerful GPU. However, with IBM/Toshiba leaving the cell playfield, they would have had to find ways to actually redesign the thing on their own. They chose to listen to AMD ("we are building the superduperchips") and are now sitting in front of a train wreck, as AMD hasn't really built rockets into their CPUs. It doesn't help either that suddenly everybody thinks how "GPGPU" solves everything and how good an A10 fits into that hype. Forget the hype about GPGPU, it is completely meaningless when talking about game consoles.

A game console has to run a game on a powerful CPU and make pretty pictures with a powerful GPU, there is no place here for the GP in a GPGPU (unless your game is about multiplying large matrices and solving linear equations - I definitley doubt such a game would sell). If we look at the latest rumours, this is what the XBoxNext has, a powerful CPU (FX8xxx) and a modern GPU (HD7xxx). PS4 lands in nowhere land with an A10 (even with a second 6670GPU tacked on).

Would an APU be easier to design games on then a CPU+GPU console?

They'd be the same, but would use less power and be cheaper to produce which are both good things, if they slap some fast memory into the new console then that'd also resolve the memory speed issue, they could even do an APU+GPU setup and have something close to a hybrid crossfire setup if they want.

A cell does not behave like a GPU at all, if that makes more sense to you...

When the idea of using two cells in the PS3 was laid out, your typical GPU was a pretty "weak" thing, it had a very few shader groups running at a few hundred MHz at best. So using a 8-core SPU chip at several GHz was "a lot faster" than any existing GPU, a t least on paper (and apparently they tried and couldn't get it to perform reasonably for whatever reasons - hence the GT7800 GPU tacked into the PS3 in the end). Times have changed since. Even a basically mid-range APU like the A10 has a GPU with almost 100 shader groups, running close to 1GHz. You can't stuff so many SPUs in a cell to compete with that nowadays.

The correct path to the PS4 would have been an improved cell chip, 3 enhanced PPUs and 4-6 enhanced SPUs (no need for more SPUs, as the GPU now does the graphics stuff) at 28/32nm (basically leading to a 150mm^2 chip, not much bigger than the cell chip now), and a modern powerful GPU. However, with IBM/Toshiba leaving the cell playfield, they would have had to find ways to actually redesign the thing on their own. They chose to listen to AMD ("we are building the superduperchips") and are now sitting in front of a train wreck, as AMD hasn't really built rockets into their CPUs. It doesn't help either that suddenly everybody thinks how "GPGPU" solves everything and how good an A10 fits into that hype. Forget the hype about GPGPU, it is completely meaningless when talking about game consoles.

A game console has to run a game on a powerful CPU and make pretty pictures with a powerful GPU, there is no place here for the GP in a GPGPU (unless your game is about multiplying large matrices and solving linear equations - I definitley doubt such a game would sell). If we look at the latest rumours, this is what the XBoxNext has, a powerful CPU (FX8xxx) and a modern GPU (HD7xxx). PS4 lands in nowhere land with an A10 (even with a second 6670GPU tacked on).

Wow that sounds great for Sony, I'm sure the A10 APU is a good idea then (even though some of you mentioned in terms of power it's not the greatest), it could give Sony a profitable gaming machine.