Performance: On paper, the PS3 is more powerful. In reality, it’s quite inferior to the 360. Without getting into too many details, the three general-purpose CPU’s the xbox360 has are currently FAR easier to take advantage of than the SPU’s on the PS3. I suspect a few years down the road some high budget, first party PS3 exclusive titles will come out that really take advantage of the SPU’s and do things the XBOX 360 can’t, but I don’t think the console is worth buying based on this speculation (for some it will be though, we'll have to wait and see how these games turn out).
Graphics: The XBOX 360 is a clear winner. The GPU is more powerful. It has more powerful fillrate, and far more pixel and vertex processing horsepower. Part of the reason is their choice of memory, and architecture of pixel and vertex procesing. I can’t get into details but the same vertex shader will run much slower on the PS3 than the XBOX 360. The 360 also has a clever new way rendering high definition anti aliased back buffers. To accomplish the same effect on PS3 is prohibitively expensive. For this reason I think many games will have no choice but to run in non-HD resolutions on the PS3 version, use a lower quality anti aliasing technique, or do back buffer upscaling. The end result in all cases is going to be noticeably worse image quality.
Game Selection: The XBOX 360 has a huge head start here. 1 year is an eternity in gaming. Almost all multi-platform developers have made the XBOX 360 their primary platform due to timing of release-to-market, this means the games will look and perform better on the 360. The PS3 versions will be ports of the 360 versions. (The opposite was true for XBOX 1 vs. PS2). The XBOX 360 is also far faster to develop for due to better development tools (massively popular Visual Studio .NET vs. proprietary, buggy PS3 compiler and debugger), better documentation, and easier architecture (3 general purpose CPU’s vs. 8 specialized processors that require DMA). Timing has also caused all next-gen middleware developers to make XBOX 360 their primary platform, and they will ‘add ps3 support’ as needed. This support will probably be inferior to the XBOX 360’s due to manpower and more importantly, demand. It’s this catch-22 now that will continue to drive the 360 forward and hold PS3 back.
The other obvious point here is that right now the Xbox360 already has a very impressive line-up of titles on store shelves; the ps3 just launched, and has virtually nothing of interest. Also, many 360 games are already discounted. PS3 games are all full price since it just launched.
Live: Microsoft’s online support with XBOX1 was phenomenal. They built in-house experience, user base, facilities, $$ commitment from executive level (since it proved successful), and most importantly, feedback from 100,000s of XBOX Live subscribers. Playstation 2’s online support sucked. They are now playing catch-up, trying to emulate Xbox’s model. But they had their hands tied just trying to make the PS3 work, it was incredibly ambitious (blu-ray etc.). I haven’t seen it yet, but I seriously doubt the quality will be anywhere to the level of XBOX 360.
HD Content: The PS3 comes with one built in (blu-ray). The XBOX 360 offers HD-DVD as an add-on for $200. You probably don’t care about HD-DVD right now. But you will soon (The quality between DVD and HD is comparable to VHS vs DVD, if you have the right TV) so I suggest paying attention to the war that’s begun. There are two formats: HD-DVD and BLU-RAY. Basically if you rent a BLU-RAY DVD from Bockbuster, it won’t play in your XBOX 360 HD-DVD, and vice versa with the PS3. The implications of this format war would require another article on its own. But as far as the consoles are concerned, the XBOX 360 wins because the DVD player is a separate unit. Playing movies is very taxing on the DVD reader, and let’s face it. In 3 years when your PS3 DVD drive goes out due to playing lots of movies (PS2 was notoriously bad about this) you will have to go buy another PS3. With the 360, you’ll just chuck your HD-DVD player, and go buy another one at the store. In 3 years standalone units wlil probably only cost about $99-150. Another point for the XBOX 360, is that I don’t know who will win the format-war, so I would rather wait with purchase of a HD player. The PS3 doesn’t give you this option.