The bad: The crossover is the sixth-season "Baby It's You", IMNSHO one of the worst episodes of Homicide ever, in large part because of the overpresence and overacting of Det. Paul "You Dunno Janine" Falsone, as played by Jon Seda (who was frankly more sympathetic playing a dirtbag Mob killer on Oz). Last time I saw this episode, I sat down anticipating enjoying a nice glass of wine with my all-time favorite TV show and ended up swilling the entire bottle just to dull the pain.
The ugly: Falsone's greasy hair. Ugggggggghhh.
BTW, I am not alone in my distaste for Falsone. There's also the We Hate Paul Falsone webpage, an entire subgenre of Homicide fanfic dedicated to rewriting the infamous "peach" scene with various lovely painful results, and this gem.