I didn't think Quiet Riot were horrible. In their heyday they could entertain, there was worse stuff out there, DuBrow was both visually and vocally immediately recognizable and Sarzo was a hotter-than-most (and I don't mean his looks though they certainly helped QR's mass appeal) bassist/poser, Cavazo not as obnoxious a shredder than most, Banali could hold a rhythm. When they were just about to break they were on a German heavy metal TV festival show together with Judas Priest, Ozzy, Scorpions, what have you. They were the freshest band of them all and held their ground. Their debut (not counting the Randy Rhoads stuff for Sony) is IMHO a minor classic of the then LA glam/hair metal scene. "Metal Health" still draws a nostalgic smile to my face today. It's mindless, but pleasantly so.
I remember reading that DuBrow was unaware of Slade or Noddy Holder's existence at the time of the recording of that debut, he said he patterned himself after Steve Marriott. It was the producer who said "You sound like the guy from Slade" and recommended covering a Slade song. Given how little Slade meant in the US while Humble Pie ruled the stadiums for a while I tend to believe that.
Jim Lea said that the success of "Cum on feel the noize" as the QR-remake bought him a nice house, he has no complaints except that he said "They did not so much cover as rerecord it!".