while ur already comparing those two (which you shouldn't, those are two completely different leagues):
"the other server" has a skyblock mode that literally outperforms every other skyblock server in each and every way, there's so much new content flying in while keeping the playerbase of 11k ( !!! ) active and happy. ManaCube has 1k "active" players combined on the whole server, and loads of those are either claiming that they are bored, complaining about stuff not changing or only coming on to chat with their friends they met on the server.
I'm not trying to talk down manacube, it's an insanely unique server with HUGE potential but it's been going downhill for a while now and change is needed to succeed imo.