Having watched "The Key To Time" recently--I agree. I found "The Ribos Operation" a chore as well. Although I enjoyed "The Power of Kroll" 20 years ago, I find it weak now too. "The Pirate Planet" is an all-time favorite, and "The Stones of Blood" was solid. I've been watching Tom Baker in order for months now- the Phillip Hinchcliffe Era was consistently great. I've just given up on Season 18. I absolutely hate the changes John Nathan Turner made to the program. JNT took away everything I enjoyed about show away. Season 18 is so bland to me. Tom Baker seems completely disinterested- he barely looks at other actors. The constant destruction to K9 is juvenile. OK, JNT- we get it. You don't like K9. Adric. I only have "Keeper of the Traken" & "Logopolis" to go but I had to stop. Playing Peter Capaldi's Season 8 now.