I have just started a fresh collection, and only have a juvie unidentified Heterometrus scorpion. I rehoused it yesterday and it literally spent a dozen hours circling and climbing its cage, it must have exhausted itself or acclimated because I haven't seen it for hours now.
As far as favorite species go, certainly Heterometrus would be one because of their crushing claws, large size, and they're feistier than the Emperor. These scorpions have a certain fascinating behavior or "character" even.
However I find Leiurus and Androctonus, and certain Hottentotta and Uroplectes species sexy af.
But a real personal prize would be the Urodacus being introduced to the US hobby.
Currently only have 11 scorpions and only 3 species. I've got 2 pandinus imperators 8 centruroides gracilis and 1 heteroctenus junceus. My favorite that I own currently is my H. Junceus. I'm hoping to get more in the near future. I'd also like to get some hottentotta franzwerneri, uroplectes fischeri, olivaceus and chubbi, babycurus jacksoni and gigas, h. Spadix, centruroides bani, altagracia, vittatus,hentzi, and limbatus, lychas mucronatus, tricarnatus and a few others. I love them all!!