I need to keep notes on the renditions I hear - because I'm always forgetting things. I just heard (again) Michael Tilson Thomas' 1990 version with the L.A. Philharmonic / Ensemble - and it really is pretty good. It is very creative and alive. One gets a feel of being in the 20s - but not patronisingly so - and still the majesty of a Ravel-like classical orchestra is preserved. I think it is not surpising that the version comes out of L.A. rather than NY, because L.A. was so key to the whole 50s thing, even though the first performance of R.I.B. was in NY.
A note to Desiree - I think it was Gershwin's Concero in F. - I'll have to hear it again to be certain.