The plot: A group of yuppies get stuck in the bad part of town, become witnesses to a murder, and are relentlessly hunted down by a gangster who doesn't want any witnesses.
Judgment Night is the sort of stereotypical, clichéd 1990s thriller that was quite popular: gritty, urban, dark, and starring a young, recognizable cast that seemed well on their way to the A-list. Ironically, few of them managed to retain their popularity for much longer. At the time, I remember being a big fan of pretty much everyone in this movie, though.
I've always thought this movie was somewhat underrated, but I can understand why some people dislike it. It's not an incredibly original story, the protagonists are sometimes stupid (and usually annoying), and it apparently takes some liberties with the setting. Not being a Chicago native, I can't really comment on that, but it seems to be a sore point for some.
Much like After Hours and Very Bad Things, this is a movie that relishes the opportunity to continually push its protagonists into increasingly nasty situations. However, unlike those movies, it's pretty much a straight-up thriller, without the black humor. I'd recommend this movie to fans of gritty, urban thrillers. It's nothing they haven't seen before, but it's an enjoyable rehash, nonetheless.