bratch, i'm a proud owner of both the M1 and M2. I absolutely swear by them. I got my M1 as a present from my dad when i was 14 or 15. im now 22 and have shot thousands and thousands of rounds threw it. I've killed enough ducks, deer, bears, doves, turkeys, swans, geese.... to fill up 3 dump trucks with these guns. If you clean them they'll last forever.
The big difference to me is that the M2 does feel a little better in the hand and mounts easier as well as having those little jell things in the stock. I really dont think that it makes the recoil lighter or anything but both are great guns. I def suggest that you buy one of the two and you will not regret it.
You talk about fair price... well actually there are two dif kinds of M1s. The easiest way to tell is look at the safety on the M1. The first generation has a circular safety and the newer generation has a triangluar safety. That'll kinda give you an estimate of age(triangular safety started maybe.... 7-8 years ago, just guessing). For the first generation, around here, well used are going for $650-700 if they are beat all to pieces. Gen2's in the $700-800 range.
Prices in my state may differ dramatically because everyone "uses" shot guns for hunting and the benelli's are extremely popular.
I hope i answered some of your questions, sorry it was so long.
