Hocus Pocus and Abracadabra both come from the same era of psychedelic rock. They're both good songs, but I'd say that Abracadabra falls more in line with Steve Miller's larger catalog, while Hocus Pocus is just kind of a weird one-hit-wonder by Focus.
I think a lot of the appeal to Hocus Pocus is just the fact it's kind of weird and absurd. Abracadabra sounds better as an actual song.