Maybe it’s trendy to hate on Koontz but I enjoyed his books when I was a bit younger. The Face, Watchers, TickTock and a couple others but I also liked Clive Cussler at the time so there is that. I think I found it easy to pick up and read as opposed to an investment like King.
A quick google says that Koontz has sold 450 million books and is worth over 200 million. I’m sure he is okay with not being some people’s favourite.