I think it just depends on eating style, price of entrees (as you've said), and what you'd pay otherwise... I would just look at some signature menus of restaurants you like and make your own determination. The hard and fast "bad vs good" use of table credits varies a lot between dining plans, anyway.
It's my future plan to buy the deluxe dining plan, and do one TS breakfast (or lunch), use our snack credits as a light meal/snack for morning or afternoon, and then do a signature every night. Already looked at menus, and based on where we would eat and what we'd like to order, we come out ahead and "maximize value" on the deluxe plan.
Now, whether that is cheaper than just using Tables in Wonderland... still calculating