The Ps3 has always been able to run Linux and now in game mode we no longer have to worry about the hypervisor restricting access to the RSX.
Graphics should no be much more powerful.
But I wouldn't overestimate the power of the Cell processor. If you only take the PPE into account (and don't consider the extra power provided by the SPEs) than the processing power of the 3.2 Ghz Cell, because of its in order execution pipeline is actually lower than the processing power of the 1.8 Ghz 7447 (G4) in my Powermac.
I do think its a neat system and it offers a good performance/price ratio.
And since their is a PPC Linux hosted version of AROS already, it shouldn't be too hard to get AROS running on a PS3.
The only negative I see is that I can assemble an X86 AROS system for only a little more and that port is the most polished. But so what, we're hobbyist and I say if it can be done, why not?