I'd stay away from any PS3 aside from the newest one that has a 45/40nm CPU and GPU.
I, Personally would wait until they have the CPU and GPU on the same die and at 32nm. (Not sure if this is planned but it might happen.)
I'm not saying that PS3s are unreliable. I'm just saying they consume a good bit of power (not sure how they compare to 360) unless they're the 45/40nm version.