Tooky,
I've got 2 12 ga. M1 Super 90's and they both pattern great. I've had good luck with a Kicks GT .660 for the Winchester Xtended #6, and a Comp-n-Choke XXX Full for the Winchester Supreme #6 lead loads. Both will kill a turkey clean at 40 yards.
One of the guns shoots a little low, but I changed the stock shims and it helped a lot. I have a 2-7 Leupold shotgun scope on the other one.
The trigger on one is a little heavy, but it breaks pretty clean. The trigger on the other is a little heavy too, and it has some creep. I'd have them worked on if I knew a gunsmith I could trust, but they aren't bad like they are now.
I had an SBE, but the pattern difference was so small I stayed with the 3" guns and sold the SBE.
I would highly recommend the pistol grip stock for turkey hunting.
I've been turkey hunting with Benellis for about 6 years now, and I am well pleased with them.
Just my opinions,
Hope that helps.