Of course there are alternative controllers available, but here's Mike Ferro's analysis on the standard 360 and PS3 controllers:
http://gamer.blorge.com/2008/11/22/analysis-ps3-vs-xbox-360-controller-comparison/
My take: Overall a nice analysis, but does not address all aspects.
For games like Ape Escape or Super Stardust HD (games I like and own) the symmetrical nature of the analog sticks feels a lot more natural and is far more effective on the PS3.
I also like the motion sensing ability of the DH3 which the 360 controller does not provide. For example the flying parts in Ratchet & Clank: Tools of Destruction or a game like Super Ruba Dub. With LittleBigPlanet you can make a lot of gestures, like shaking your head or looking at and pointing towards something when playing online with people (next to chat communication). I like the triggers, pressing them a little further you can get your sackboy to point fingers at things instead of just waving your hands for various gestures.
Although I can manage with both controllers myself, I will have to note my girlfriend and sister both got hand cramps from using the 360 controller (and not from using the PS3 controller). Of course there are others who say they experienced the exact opposite to be the case for them, but note there are hundreds of million of gamers out there who used similar controllers as those standard with the PS3.
In the end its all very subjective and depends on personal preferences. But you hear 360 fans all the time about how the PS3 controller sucks and the 360's controller is vastly superior, I thought this analysis to be an interesting read.
My opinion as a physical therapist and the ergotherapists I know is that the PS3 controller is better designed overall, it more easily fits more different kinds of hands. For the symmetrical nature of the analog sticks this is also the case, better suited for both left and right handed people, the active range of motion is a handicap for the left 360 analog stick (especially an issue if you have left-hand problems or small thumbs).
