The SBE2 is a great gun, and I don't blame anyone for suggesting it.
However, the feel and fit of the gun to you are going to be the most important thing.
I bought a new A5 about 4 years ago. I used it for a year and liked it. I eventually caught the SBE2 bug, and I sold the A5 and bought a SBE2. I'll never complain about the quality of the gun, but it just didn't feel as good to me. I didn't shoot it real well, and I had a bit of a tough time finding a good turkey load/choke combo. I sold it and bought another A5 and have never looked back.
I won't say the A5 is better than a SBE2, a SX3, a Versamax, or any of the other popular auto-loaders, but it simply fits me best.
For turkey hunting, I'll never use a 12g again. I got hooked on 20g with TSS last year and it's all I'll ever shoot from now on. I get outstanding patterns and performance from lighter guns with less recoil than most 12g guns.
A 20g is also plenty for dove. However, I want a 12g for "random" duck hunts. If I knew I'd always be hunting over decoys and shooting them in the face, a 20g would be fine. I'm like you though - I just go when invited, and I like to have a 12g for those situations.
Go to some gun stores (somewhere like Gander with a huge selection) and hold as many things are you can. All of the major manufacturers make reliable auto-loaders. You just have to find the one that fits you best.
If I could only own one shotgun, it'd be a new A5 12g with a 26" barrel. Instead, I split my work between a A5 28" 12g and a M2 26" 20g.