The scattergun technologies for me.. No doubt the Benelli is one of the very best, but i prefer the 870s and they come with some excellent features ie. sure fire light, side saddle, tac sling, and tritium sight.. I saw on American Shooter that Benelli has made a new model for the USMC, i don`t know if they will be availabe to civi`s but it would be worth lookin at if you decide on a Benelli.. my 2¢
get the benelli, I've got a super 90, and I've owned a couple of 870s and a 1100. the benelli is superior to all of them, utterly reliable, super fast cycling, but it does kicks like a mule. especially if your going to use it for 3 gun matches, your going to want the speed of a semi over the alledged reliablity of a pump.
Rem. 870 gets my vote. I have been issued Benelli's and used them quite extensivly but I still prefer a pump. Less to go wrong and not picky about ammo. It is really a matter of personal preference like most gun choices.