The Black Hole is indeed worthy of watching and considered a cult flick, but as compared to other science fiction films, whether Star Wars, Star Trek, 2001, 20,000 Leagues, Blade Runner, Silent Running or even Dune, it fell short.
The film had a decent budget for the time, and some aspects made that evident but the special effects and editing just couldn't keep up with the ambitious scope of the storyline. Also some technical aspects were really poorly handled in writing which carried straight through to the big screen.
Nevertheless despite these traits, there's something about it still worth watching.