Personally I'm not a fan of 360, I much prefer PS3's.
My reasons for this are that I don't really like the 360 interface (like the dashboard) but that's my own opinion. I don't like the idea of having to pay to go online (I couldn't give two shits whether it's better) as many people spend £100 odd on setting up a wireless network in their home, and should be able to connect and play for free. Another thing is that 360's don't have WiFi built in (I may be wrong with the Elite version) but I'm not going to pay £50 for a wireless adaptor which basically comes built in a PS3. PS3 has a Blu-Ray player, (yes many 360 users say "Oh yeah but what's the point of it, DVD's are just as good). Fact is that they're not, the quality is by far better, and 360 users have to buy a HD Movie player to play those HD DVD movies that I've seen in the shops. The price as well, 360 users tend to say that PS3 is overpriced and you don't get value for money, I spend £400 on my PS3 on launch (which was 2007) and I've never had a problem (in that space of time a 360 usually gets a RROD once or twice, in which case you need to send the console off for 3 weeks and that means no play, and 3 weeks of XBOX Live subscription wasted which you don't get refunded), in the £400 I've also got myself a Blu-Ray player, Internet Browser (which 360 users don't have) and some other good stuff which comes in handy. PS3's controllers are motion sensitive, something that Microsoft never placed into their products (Racing games feel 10x better with a motion controller, ask any Wii user). You also get a bigger hard drive than most 360's (I think Elite has a 120Gb but PS3's 160 combats this), you can also put an external hard drive into a PS3 anyways and for example put 1TB on your PS3.
Overall I love my PS3, I'm not saying 360's are crap, but from my perspective I think PS3's are better and they suit me better, and I prefer them