No, this isn't 2007 when crappy PlayStation 3 ports abounded ('cough' The Orange Box 'cough') but even so, we still can't seem to leave such unpleasantness behind. At least, not entirely.
EA got in the doghouse early by shafting PS3 owners with Madden 09 ; the version for Sony's machine ran at only 30 frames per second while other versions fared much better in that department. EA has since cleaned things up and we haven't seen many significant differences between PS3/360 versions of their games. But just this year, despite Sega's assurances, Bayonetta lagged on the PS3, and I had to remind everyone that the 360 version was a 9+ game (as most sources claimed). Just recently, Mafia II underwhelmed critics; the console version was significantly inferior to the PC version. I'm not sure if there were clear differences between the PS3 and 360 versions, but the point is that Mafia II is best played on one platform above all others.
There does appear to be a formula that seems to work almost 100% of the time: if a game is made on one platform first, and then brought to other platforms, the original platform invariably gets the best version. If the designer works on all versions simultaneously (and most are doing that these days), nobody gets ripped off. Platinum learned from their mistake with Bayonetta and made sure that the upcoming Vanquish wouldn't piss off PS3 owners. They did use the PS3 as the lead dev platform but they already had a working knowledge of the 360 after their stylish action slashfest earlier this year. But the problem still exists in the industry and if exclusives don't promote multiplatform gaming, the shoddy ports do. Hardcore gamers have always been better off with multiple options, anyway. If you're willing to shell out, of course.
So if you were only a 360 owner and were considering a PS3 purchase due to games like Uncharted 2: Among Thieves , God of War III , Metal Gear Solid 4: Guns of the Patriots , Gran Turismo 5 , and Heavy Rain , you'd also like to know that Final Fantasy XIII is probably best played on Sony's machine. If you were a PS3 owner, and titles like Gears of War 2 , Alan Wake , Mass Effect 2 (yes, it's coming to the PS3 but you wouldn't have known that back then, would you?), Fable II , and Halo 3 / Halo: Reach didn't entirely convince you, it'd be good to know that Bayonetta is best experienced on Microsoft's console. In the end, we want the best versions of games we intend to play and as of yet, they're not all identical across all major platforms.