Unless you truly will do a character buffet daily (and keep in mind if your child is like mine, you will set up an expectation for the next trip - which I know I wouldn't pay for our of pocket!), and do not care about extra space (some families do not), I'd do offsite.
We did FD bounceback last August. My kids often share a meal - they nor I can (and I don't want to - I gain weight!) eat all the food. DH hates being crammed into 1 hotel room. I didn't like the stress I felt to make and keep ADRs in a manner to make sure I got all the 'value' possible - and still had 17 CS credit remaining on the 2nd to last day! (And, sometimes I didn't like the dessert options at a CS. So I endlessly planned which CS to eat at - to get the most value. A pain.)
Anyway, I booked FD for this August (as bb from Aug 2014). I've canceled it and we'll stay at Windsor Hills instead. 3 bedroom, 3 bath, 3 tv, full kitchen, private splash pool (and community pool with long slide) for $100/night with tax. I can feed us for $100 a night, but even if its $150 or $200 we are not crammed into a small hotel room. I'll pay less for a 3 week stay at WH vs. 10 days at POR. Of course food will be on top of that, but I don't want to do TS daily anyway - too much stress surrounding the process.
I guess the savings of FD is different for every family. I remember one Disser who said she'd rather eat saltines and peanut butter (offsite in a multi-bedroom rental) than be in 1 hotel room with FD. I agree, and I'm a very frugal person who has a disabled DS - Disney adult - who LOVES character meals. Oh - and we rent a car anyway, so that is not an extra expense to us for offsite.
Good luck!