I just ant to play PS2 games on my PS3 like we were originally promised. I'd hack it for that. Unless Sony starts selling PS2 games on PSN, then all would be good.
You'll be lucky, the only reason it worked on the original systems is because they had half the PS2 hardware in there. Without that hardware you'd be limited to running a software emulator, and PS2 *software* level emulation is nowhere near the quality needed to play games on a PS3, and probably never will be.
I own both systems, and while the recent press about Sony possibly acting against the used games market by having one-time redeemable codes for online play annoys me, as does the limited access to the hardware from Linux (and complete lack of it in the later models) I don't really think it being cracked would be a good thing at this point. It's the less popular of the two systems by quite a margin, but a lot of developers still see it as worth porting their games over, and even developing exclusives because they're guaranteed sales as opposed to simply having their games copied.
For titles which are on multiple platforms in 99% of cases the XBox versions appear to be superior, the PS3 suffers with framerate issues, and overall (despite the hype) is in my opinion the weaker of the two systems as you have far less general purpose CPU power available (1 PPC core. vs 3 PPC cores) even if you have 6 extra SPEs (which are effectively special purpose cores) on the PS3. The problem is, a lot of tasks can't be split easily across multiple cores, and while the SPEs are powerful, and fast they also have strictly limited access to memory, and if you're not careful you'll just end up with severe contention issues in your game / code. This may explain why the cross-platform games are weaker, as the Xbox is easier to program for as it is generally closer to a PC, and PCs are almost used for development.
That said, I've actually enjoyed the exclusives on the PS3 a lot more than the ones on the XBox.
MotorStorm Pacific Rift is a great game, all action racer, very arcadey, and honestly the most fun I've had with a racer since Hydro Thunder.
Lair, despite the bad reviews is pretty good once you've got the patches installed so you're not forced to use the motion controller for certain actions.
Demon's Souls is a proper gamers game, and while it lacks a little polish, and in reality isn't a huge game it's a challenge that you'll keep coming back to because you want to beat it. Took me ~60 hours to complete the game once, but you can play through it again and unlock / upgrade to new weapons the 2nd time through (in which the enemies are 50% tougher!)
Katamari Forever is great fun if you like rolling things around (although their use of the motion controller for jumping is annoying as you can accidentally trigger it without wanting to)
Heavenly Sword is worth playing, albeit a little short.
Infamous reminds me of a futuristic Assassins Creed.
The game that I worked on a while back 'Geon' has it's best version on the PS3 (PSN), as it was developed a long time after the XBLA version and contains significant enhancements (I'd actually consider it to be a different game completely as it makes the XBLA version look more like a prototype concept, almost everything has changed)
LittleBigPlanet is a fantastic retro experience, and great with 2 players, it's a shame so much of it is online content tho, it would be nice to see some BluRay discs released with 'the best content' because I'm not a big believer in online content / games because I know they're only a temporary thing, and once the servers get shut down they'll be gone for good.
"3D Dot Game Heroes" is almost a remake of the classic Zelda games, I've played it on import, but I'm waiting for an actual US / EU release to buy it.
Uncharted 1/2 are well made cinematic experiences, with some shooting elements, and some stealthy elements which remind me of the original Metal Gear Solid more than MGS4 does.
The Rachet & Klank games are what you'd expect from such games, cutsey experiences and they actually make pretty good use of the motion aspect of the controller
KillZone 2 / Resistance are probably my least favourite of the exclusives.. They're just generic FPS games and remind me more of the Xbox games I was already bored of.
There are also a good selection of other PSN exclusives, which again I wish had Blu-Ray releases (some do in Asia, but nowhere else for some reason)
I doubt GT5 will be any good, Forza 3 on the 360 has covered all bases, providing everything from an arcade experience to a serious simulation depending on your choice of options. The developers of GT seem too stuck in their ways, and are unlikely to produce anything except a game with a lot of content (half of which I imagine you'll have to buy after the game), but dated gameplay. I'm not looking forward to it at all, and it's not even on my radar.
To say it's a better system than the 360 would be foolish, it definitely lacks some polish, but to say it's not worth owning is equally foolish as the exclusives really are worth playing. Most games will install anything from a few kb to about 4gb of data when you first run them, and most have significant patches to download after installation (while this indicates good support, it's also a bit annoying that you can't just download them and copy them to a memory-stick for offline installation) MGS4 is the only game I've played that has significant ingame installation periods. The controllers are lightweight and charge via a standard USB cable, and as stated you can swap the HDD for a larger one if you feel the need. The whole 'home online community' thing is a bit of a joke, it's been compared to Second Life, but the only point of Second Life was that you could build and program your own items, the home thing is just a glorified chat-room where they want to sell you extra items and clothing; it's not worth either your time, nor the space it takes up.
I do fear that if the system is cracked a lot of developers will stop developing for it due to the much lower user-base, and greatly reduced chance of any profits, and as a result the machine will end up going the same way as the Dreamcast.
If you have one of the 'fat' models where you can run linux it is actually possible to compile, and run MAME on them right now. However, performance isn't great, and definitely isn't comparable to a modern PC. As far as MAME is concerned all you have is one relatively weak PPC core to run the emulator on. The SPEs are useless for emulation (which isn't something suited to lots of small tasks) and even if you did have access to the full system hardware you wouldn't really see any benefits as far as MAME is concerned. It's a nice novelty to be able to play with it, but if you're expecting to play anything slightly demanding in MAME you're far better off sticking with a cheap modern PC as the PS3 simply doesn't have the CPU power.
Anyway, that's my honest opinion on the systems as an owner of both