It depends.
I'm kind of take it or leave it.
Last trip there we had dinner at the Liberty Tree- the all you can eat family style turkey/pork/beef thing.
I personally find it horribly overpriced ($30-40 range per person if memory serves) to basically eat carved Old Country Buffet style carved meat, and mashed pototoes/stouffers mac n cheese, but my all-American plain jane eating parents who I could never get to eat Mexican/Japanese/Italian food love the place (I found myself wishing I was eating pretty much anywhere else in the Epcot world showcase instead). For me, my $40 spent could would have much happily gone to an outright exquisitte dinner at many other places in WDW.
I never did lunch there, at least they have an actual menu then where you can choose different things other than the "thanksgiving platter", so that might be more appealing if the dinner IMO, plus pricing would be more reasonable.
Still, all that said, its decent sit down dining in the Magic kingdom- where there isn't a ton of choices, so that counts for something too. Any moment spent in the MK is great to me. If thanksgiving dinner sounds right up your alley, you'll probably love the place.