I use it occasionally and it works much better than any filter in PS. It does create detail, but not real detail of course, but it somehow finds where to (and where not to) add detail. It keeps straight edges sharp. Sometimes I enlarge with GF, paste it in a second layer which is enlarged using PS and get rid of the the parts with less 'detail' in this GF layer (sky, e.g.), where extra detail is not intended. I might post some test... if I don't forget.
---Dune