They are too close for one to be a better console. I have both so here's my opinion:
Price
There is no price difference. I think i'm right in saying that £159 is a good price for an Xbox 250gb slim and £191 is a good price for a PS3 slim. You only have to add 1 year GOLD and a rechargable battery solution for the price to be, at best, as much as the PS3. Any small difference thereafter is not enough to choose one over the other. The fact that a 4gb model and an arcade exist is irrelevant because anyone who is 'into' games enough to be posting here would either A: never buy one or B: be all over bargain sites after a HDD from day 1.
Exclusives:
I still think that the PS3 has better exclusives but it's a matter of taste. There's plenty of people who love Gears of War and Halo. There's nothing wrong with that.
Controller:
Again, it's preference. I'm fine with both. I've always said that if pushed for an answer, I'd say the Xbox one is better but I'm quite accustomed to the PS3 controller. Be open minded, the chances are if you use either one for a year or 2 and then try the other, you won't like it. That doesn't mean it's worse.
Online:
I don't see much difference here but I'll accept that the general opinion is that the Xbox must be better somehow.
Trophies/Achievements
I have to say, the xbox version is far far better here. I never understood how this could be untill I had an xbox. It's even seen me firing up PC games for windows games to add to my gamerscore. With the PS3 I would never look what trophies I was missing etc With Xbox I'm always looking at achievements.
Graphics difference:
You will never win here unless you have both consoles. More multi-platform games seem to better on the xbox but there's rarely much in it. there's also plenty of games that have the edge on the PS3. Some PS3 exclusives look better than anything on the xbox but this late in the game, there's not exactly bucket-loads of games that this applies to. At this point, you could add in games that are 3-4 discs on the Xbox but 1 disc on the PS3.
Overall, I'd say I prefer the PS3. Even so, I think Sony messed up a bit here. Considering the Xbox 360 had already been on sale over a year, and these initial sales were already lost, I think they should have held out another 6-12 months and even upped the price from £425 to £499 (who would pay one and not ther other??) and gone to town with the GPU and extra RAM. We wouldn't be having this discussion if they had.