Anyone know if there is any new functionality other than the newly supported cameras?
As far as I can tell after a quick check-out, the colours of Konica-Minolta MRW and Sony ARW raw images rendered with ACR finally match the JPEGs' shot in RAW+JPEG mode (rather than being awfully pink). Don't know if that was a problem with other brands' raw files too, and if so whether it now got better with those. For me, being a Konica-Minolta and Sony DSLR camera user, ACR 5.4 is a major improvement over ACR 5.3 and earlier versions ... ummm, or maybe the improvement is not due to ACR proper but due to the camera profiles coming along with it. Anyway, it definitely is an improvement.