Ok, while this will only be my second year duck hunting I've been competitive shooting for 10 years, and I also worked at Dick's Sporting Goods in the firearm department for a year and sold many VM's and SBE2's. I've hear multiple testimonies from everyone from 12 year old to the old guys that have been around before Moses. Here's what I've heard and have seen (I've shot both):
sbe2: I sold these mostly to people who haven't done quite as much research. Most of them are going based off of the Benelli name or because their buddy had one in the blind. Take that with a grain of salt cause there IS a reason that Benelli got its good name. After quick review, the sbe2 is an amazing gun that just about everyone who shoots it loves and they will wear by it over the VM or any other gun, even the Beretta A400. Another pro is that due to almost all the parts, especially exposed part, are coated and prevent rust better than most all other guns. I had multiple people tell me they clean it about every 3 hunts (why you wouldn't do it every time beats me).
Best story regarding the sbe2: A guy probably early 50's came in and bought a sbe2. He had gone out the week before and went with a buddy who had one. When they went out his friend dropped the gun in the lake. He picked it up, put three shells in it and it racked them out no problem, even with water flying from the chamber with the shell.
VM: Most of these guns were sold to guys who were Remington loyal from something like their field 1100 or daddy's 870, or because they had done a lot of research and shot it and loved it. From most of what I remember the VM got a bad name because of faulty parts in some of the first models. As far as recoil is concerned I've heard guys of all sizes compare a 3" shell to a light target 2 3/4".
Best story: A guy came in a bought a VM from me in late October. He already had a sbe2 but the VM was on sale and he figured he'd get his son a better gun than the Mossberg 500 he was using. Around mid December he calls my store asking if we have any more VM's. Comes by later that day and buys two. Turns out that after almost a month of hunting he had tried out his sons VM a couple times, loved it, sold his sbe2, and was now buying himself a VM sportsman for duck hunting and buying one in mossy oak breakup for turkey.
Here's my opinion: I took them both trap shooting. I liked the feel of the sbe2 because of its complete rounded forearm. I used the pointed finger technique for my forearm hand and the VM's didnt feel right because of the cut. They both shot about the same, but the recoil was less in the VM. Both ejected the Remington STS rounds fine, but when it came to Diana only the Remington cycled every time.
In conclusion: I'll put it this way, after working in the arena and hearing all I've heard I'm now saving for a VM; however, whichever one you get you will never regret. With proper care each will be nearly immune to rust and both will get the duck. It's all up to which one you feel fits the best and which name you want to carry.