Well, after my Mossberg M590 screwed me at the last 3 gun match, where I had 3 failures to extract with Rottweil heavy game #6's and Remington #7.5 dove loads, I bought a Benelli M1 Super 90 Tactical with the 18.5" rifle sighted barrel and haven't looked back.
I've put approximately 350 rds down the barrel so far without a glitch, the vast majority being Winchester 2 3/4" standard (non magnum) OO and #1 Buck and Winchester and Federal 2 3/4" Tactical OO Buck, along with 40 Winchester 2 3/4" standard 1 oz. slugs.
No failures so far, even with light Fiocchi #7.5 dove loads.
I've owned two Smith and Wesson M300 Police guns, Mossberg M500's and M590's, and a Franchi SPAS-12. I've also used numerous Remington M870's and they are fine guns.
Out of all of them, I have to say that I am amazed at the Benelli's simplicity and cycling. A well made and maintained pump is great, but all mechanical things will fail eventually. I'm hoping the Benelli will continue it's track record, I've shot a bunch of them before and a couple of friends own them without problems, so I have some faith.
I'll agree that the Remington is probably the way to go with a pump, they certainly have the best track record.
I'll have to put my vote in for Benelli though for most reliable semi-auto. Kind of like the AK, so damn simple it's scary.