If you are looking to keep your cost down you can't beat the Remington 870 Super Mag. You can pick one up for less than $350 and pickup a aftermarket thumbhole stock for just under $100. I would have to agree that thumbhole stocks provide an excellant feel. Of course you can go cheaper than that if you don't have to have a gun that handles 3 1/2 shells. I have been turkey hunting with a 870 Magnum (3") for many years without issue. I have an Undertaker choke tube and I won't hesitate shooting at birds out to 45 yards. Outside of that it gets a little dicey. You can pick a run of the mill 870 up for $220 at pretty much any sporting goods store. I have a buddy that has a Benelli Nova and likes it a lot. You can get one for about $350 or so. I haven't shot it so I can't provide anymore insight than that. If you are going to spend the money on a 11-87 you might as well spend a few more dollars and pick up a Benelli Super Black Eagle II. You really can't beat this shotgun for any kind of hunting activity. CB375HH can tell you a good story about a turkey he took last year with a Super Black Eagle. I am not a big fan of anything Mossberg. I have never owned one but the build quality seems to be lacking and a little sloppy. I haven't really heard too many people complain about them so they must go "bang" when you pull the trigger.
"Chance favors the prepared mind" - Louis Pasteur