Thinking of booking here, is it good? Quite expensive so looking for some reviews please.
There are many pieces of data that go into the calculus of making dining choices.
You will likely find that reviews here on DisBoards will range the entire spectrum from horrible-to-amazing. But....
Simple answer - as Disney Signatures go (hence, the high-price point), then Tiffins is fine. Some folks may balk at the 'exotic-flavors' throughout the menu, but if you're OK with that, then Tiffins is something of a stand-out.
If you are seeking those 'exotic-flavors', then Jiko may be a 'better' restaurant, albeit
not inside a Park (at Animal Kingdom Lodge, AKL).
If you want to try a buffet of similar flavors, Tusker House (inside a Park, and with characters), or Boma at AKL. Breakfast at Boma is a standout meal.
And then there's Sanaa - also some of those same flavors, but a non-character, non-Park, casual sit-down (at a lower price-point than Jiko and/or Tiffins). Best times to go to Sanaa are during daylight to enjoy the animals on the Savannah. Regardless, you can enjoy viewing those same animals (and more) from public vista points throughout AKL.
We prefer snacks and cocktails at Nomad Lounge next door, but Tiffins is fine.