Essentially, the comparison is put like this: the 360 has more memory, the PS3 has more "processing power", and that makes them even.
Naturally, the consumer has been trained by CPU makers that "processing power" is everything. Pay hundreds more for another Ghz on that processor; it's worth it. Bigger is better, remember?
In the end however, I'm sure consumers have noticed that although clock speeds have been increasing, while perceived performance has not. Hell, a P2 400Mhz is plenty for an XP machine that is only used for surfing the internet. A 3.0Ghz P4 isn't going to completely outshine a 2.5Ghz P4 (Hyperthreading/Celeron considerations aside) to the impatient eye.
What could my point possibly be? Both the 360 have 3.2Mhz processors. The Cell can run a few more threads, but it has less potential memory to allocate to tasks. My point is that processing speed/abilities is only part of the equation. You can have a hot V8 motor, but if it's on a Geo Metro chassis, then it won't do you much good. The PS3 shouldn't be considered as a victim of said hypothetical situation, but it is in a less severe version of the analogy.
Neither console has a complete advantage over the other hardware-wise. Features could be used to differentiate the two, but today's consoles can be updated, allowing for feature addition and removal; the addition of 1080p support to the 360 was a good example.
Lastly, Dyacks opinion on the Wii, mirrors my previous concern; "Will the controller stand the test of time?"