Heather had the most iconic moves, but the worst gameplay. I honestly feel like her WT version (strategic mean girl but not actually antagonistic) was best Heather.
Alejandro was much more threatening and truly knew how to play people like a fiddle. In fact, I would argue he was the most dangerous (really only in danger of going home during Broadway because of horrible team composition/new player disadvantage and the final four (but he survived the first fake elimination ceremony there legitimately so give him some credit.
I do think Heather's downfall was better but I think I just prefer Al better in the villain role.