Personal preferance man. Graphically, I think it will look slightly better on the 360 since it is most likely being developed on the 360.
As for the controls, again personal preferance, but I prefer the 360s. It has an actual trigger button and the sticks are placed better in my opinion. The 360's controller was built from the ground up to have everything placed where it felt best. The PS3's, well not so much. If you look at a ps1 controller and a ps2/3s what is the difference? The analog sticks, nothing else changed. This tells me that Sony placed them there as an after thought. Again this is my personal opinion, and I'm not saying the stick layout doesn't work on the PS3. My hands just prefer the staggered analog sticks and not the horizontal. I may have just started another war, but I will enjoy this game just as much or more than anyone on a PS3.
Why? Online. Live has a ton more people on it than the PSN does, and that is a fact. Check sales numbers if you don't believe me. Every online multiplayer multiplatform game sells way better on the 360. For example, I just saw a figure a few days ago that said MW2 sold like 5.7 million copies on the 360 and 1.5 million on PS3. So what's my point you might be asking? Paintball is not a huge huge sport, especially on a video game perspective. So the number of people that will buy it on each system will be low. More than likely lower on the PS3. It would sometimes take 15 minutes to get a full game in NPPL, and got to the point where I couldn't play online anymore because a match would last 2 minutes and then there would be another 15 minute wait to play another....I am hoping they fix this problem some how, but without adding bots or something I dunno how they can.
100% truth here.
Graphically, multi-platform games typically look slightly better on the 360. They are developed for the 360 and the 360 has the superior GPU. The difference is getting less noticeable though as developers are getting better at ports to the PS3. But PS3 exclusives made by developers in bed with Sony that can utilize the Cell Processor properly do look better than most 360 exclusives. This is due to the superior CPU in the PS3.
Controllers are 100% preference. I prefer the symmetry of the PS3 controller, though it is a touch small. I really liked my wireless Logitech PS2 controller. I don't think many quality aftermarket PS3 controllers exist.

I just find the offset analog sticks a bit wacky. If the right stick is in the correct position to reduce finger/hand strain, then the left must obviously be in the wrong position, and vice versa. But again, this is just my preference.
PSN does have fewer players. Might be an issue with a non-mass market game like this. We'll have to see.
No offense, but freeman, you really sound like a clueless fanboy when you make statements like that. The PS3 is not perfect, neither is the 360. To completely ignore the faults of the system you own and the merits of the other system is a gross error.
Pickles FTW.