We just made the same choice, and we chose Christmas, even if Free Dining comes back. This was for a few reasons :
1) Because of the people on the trip, the option of renting a condo off site sounded good (though we are usually on-site people); we would have had to have two rooms at a value (the suites at the values don't get free dining).
2) It's much cooler and drier in Dec than Sept
3) We did
MNSSHP last year, and while we love it we'd like to try
MVMCP
4) The crowd reports for free dining this year were pretty bad, and we felt like when we did Free Dining last year we spent a LOT of time eating and park hopping we didn't want to do , but we had ressies and had no choice if we wanted to eat.
We really, really did enjoy Free Dining in '05. We debated for quite some time if we should wait and see if Free Dining was available or not next year, but we just want a more relaxed trip this time. We'd definately consider doing it again in the future though - I mean, heck, a thousand bucks of free food for a family of 4 is one heck of a bargain.
NED