I went to the revolving restaurant (the space exists but it no longer revolves) in what was then the Westin Detroit in 1990 and found it to be a decent steakhouse. There weren't many options in downtown Detroit at that time.

Then, I was quite impressed by the food at the Olympiaturm in Munich in 1991 - so impressed that I started looking for revolving restaurants on all my travels. Needless to say, I was quickly disabused of the notion that revolving restaurants had good food.

Here is the current website for the restaurant in the Olympiaturm (which I have not been to since 1991 so I can't vouch for the food now). Flyertalkers will appreciate that it seems to have two levels business and first.

http://www.restaurant181.com/181/Business/