I had Groundbreaker and Octopunch, and they were both lackluster to me. I DID like the TFSS Double Pretenders, and having Double Pretender Megatron pull double duty as a shell for Cerebros with my Encore Maximus was a bonus. The thing is, in both their cases they gave a well-articulated inner bot that actually had a recognizable alt-mode and an interesting shell, something my G1 Pretenders didn't do (plus Groundbreaker's helmet destroyed his face paint). That's why I've been openly hoping for a DinoKing set someday as it would give me the best of both worlds like the more recent ones did.