Spinning...
I find it easier to cast them in tight places, and like FA says they are able to cast lighter presentations more easily and accurately.
I also like to have the drag set very loose while actually swinging, etc so that when a hit occurs you can allow them to take it and hook themselves (also helps with not breaking off on the initial hit which is unbelievably hard at times). Once I hook a fish I will set the drag a bit tighter or will use my finger on the spool of the spinning reel as drag - so I find it easier in the end to use a spinning reel rather than a bait caster.
Other advantage is you look like a beak... I had lots of guys get pissed last year on the vedder when I walked into a run with a spinning set up, and they would leave grumbling, leaving the run completely to myself.
Cheers,
Dan