Depends on if they can sign an alternative, and how he produces. But I think that, unless they sign at least ONE top OL FA, it will be a bad off-season.
Again, why would ANYONE want to come to Buffalo, ever? It's not like they've been a great team anytime in the past 6-7 years. Yet the Bills still get FA's.
As for Bentley, this is specific to him, not all FA's. He has said he wants to play for Cleveland because it's his hometown. Well Buffalo isn't too far away (3 hour drive), and Peerless Price proves that playing for the hometown team isn't as great as it sounds. Plus the Bills have another Cleveland native in London Fletcher, who works out with Bentley, and can give him the inside scoop. Last of all, the Bills will be able to be competitive with salary offers.
I agree that putting all your eggs in one basket isn't a good idea, but this guy is a proven Pro Bowler at an incredibly important position on the O-line, and he'll be able to play near home without all the negatives of it.