If you are looking for "any" contract that is the best deal, then I think Fidelity is the way to go. Even with their added closing fee, they tend to have the lowest prices for most things.
If you want a very specific thing, then I might go with one of the others mentioned above. I think some of them have a better selection at a slightly higher price point.
From my research, Fidelity seems to have them priced a bit lower than the rest -- but might not have what you want. For a guy like me that just wanted the best deal at the best price (which, for me, is Saratoga Springs), then Fidelity made the most sense. (Bought one from them in October that just closed two weeks ago and just submitted another offer today that we think should go through.)