I had read plenty of reviews of Tamarind Tree on Judy's Book, so there is almost no way that it could be called a hidden gem. However, it is tucked behind a random plaza in a not so neighborhoody section of the ID, and if you hadn't heard of the Tamarind Tree, there is no way that you'd stop.
The food was spectacular. The service was good, but not standout, and the decor was very inviting in a modern way.
I don't think I have much to add to the large body of review knowledge out there, other than:
Try the guava martini - very good.