I think this is the only TNG-era story that really got what made the mirror universe so appealing, which makes it stand out against everything derived from the DS9 MU. There are some things that make it feel a bit dated/cheesy (the dolphin officer, mostly), but the story definitely felt like it could've been a fantastic movie with a few tweaks here and there.
Mr. Laser Beam wrote:
^ IIRC, the mirror universe uniforms were the same as their primary counterparts, except the collars were higher and the colors were darker (plus many crewmembers wore personal sidearms or blades). Alternate Troi was the only one who really wore a completely different uniform style, for obvious reasons.
IIRC, there was something about the guy uniforms showing off a lot of muscle or something, which made me think they were short-sleeved or something.