He is at least an adequate writer of his chosen genera. I've enjoyed a few of his works, Battlefield Earth was a fun ride. Without knowing anything else about him I would say his SciFi stuff is worth picking through.
A good, solid pulp performer.
The rest of his shenanigans and legacy don't interest me. A fair number of my favorite writers have been described, with some justification, as scumbags. The art is not the artist.
