Both consoles have plenty of 3rd support, and they all have their 3rd party exclusives. In regards to the quality comparisons of the multi-platform 3rd party games, both are rather equal to each other. It was common to have a slightly inferior PS3 version to a 360 version earlier in the PS3’s life. Later, it because more of a give and take between the two versions as developers got a better handle on the PS3’s architecture. But with developers still backing the PS3 while more and more of them are using the PS3 as the lead platform, slightly inferior PS3 versions are becoming a rarity.
In regards to 3rd party multi-platform support, there really isn’t an issue anymore. With 3rd party exclusive support, you really need to look into which games you really want.
Like 3rd party exclusive support, you really need to look into 1st/2nd party support for both consoles. I’ve been very impressed with the efforts and quality coming from SONY. They are pushing themselves to be a formidable 1st/2nd party developer/publisher and have really grown from their PSOne 3rd party dependent days. So far, SONY has mainly concentrated on newer IP’s which helps keep the market fresh, hardly falling back on their many successful IP’s in the past. Hopefully, that will come in the foreseeable future as more potentially quality offerings you can only get on the PS3. Because of SONY 1st/2nd party efforts, this reason is the ace for owning a PS3 over a 360.
Don’t let anyone fool you over the “RROD fixed” and $200 360 Arcade vs. $400 PS3 price tag. The non-arcade 360 SKU’s are outfitted with the newer chipset to help prevent the RROD, but the $200 Arcade not so much. So to compare the $200 360 Arcade to the $400 PS3 is unfair since there are currently three different 360 SKU’s. And the prevention of the RROD in newer models has yet to be proven. So be careful.
So as a gaming machine, the PS3 has more that its own to offer quality and quantity software. So the bonus I see is that the PS3 serves as a very nice media center (photos, music, movies, and online). The best way I can describe this is with an analogy. Imaging you’re shopping for a new car, and you happen to come across a luxury car that’s priced high, but you can still afford it. The obvious question is that is this luxury car worth the price so you take it for a test drive. And when you do, you get a hands-on experience of something very nice and pleasing that can only be understood when experienced. The PS3 is the first console that I’ve bought that feels like it's more of an integrated a/v component than just a console. And even with the initial higher price tag, I think the PS3 will save me money in the long run since I see myself effectively using it longer than the average console lifespan (5 years). I say this because I just recent upgraded my original 60GB hard drive with a 320 Western Digital Scorpio for under $90, and that’s just one example. Another awesome thing about the PS3 is that the peripherals you can buy to expand the PS3 are non-proprietary. Bluetooth and USB mouse, keyboard, headset, external hard drives, and even printers fall into this category. So you can get want you want at a price you can afford without having to buy something “official” unless it’s your preference.
Let us know what you are going to so, but I really feel that you will be very impressed the PS3 and will be very satisfied with its purchase.