There has always been good music, it's just sometimes more difficult to find it. Also, it depends on your taste. My personal faves from the 90's include some well-known artists like Nine Inch Nails and Rage Against the Machine.
KMFDM is an older band, but the 90's is the time, for me, that they created their strongest music.
Sisters of Mercy came from the 80's really, but I found them in the 90's.
The back end of the 90's gave us One Minute Silence. Raw and powerful. Doubt my ipod will ever be One Minute Silence free.
1991-92 was ground breaking for me. Nirvana and Pearl Jam brought music back in so many ways, Soundgarden made a great album (and went downhill), Ministry produced their strongest work, White Zombie came out, and on and on. Body Count was so controversial (with Ice T) and before you call it rap, it wasn't. But, it showed us that rock had other places to go. It also paved the way for freedom of speech in music.