In my opinion Hotham is the best resort, but I can only speak for Vic resorts. Hotham has the steeper terrain and some good off piste when the snow is deep enough. Falls is a bit too gently sloped for my liking and not very challenging but it is a pretty setting. Buller is good too but the crowds often make it a frustrating place to go, even when you know how to avoid the worst lift queues.
Hotham and Falls do not get as busy as Buller because they are a longer drive from Melbourne. I stay in Bright to keep accommodation costs down and drive up to Hotham each day which only takes 45 minutes on a good day and an hour if its snowing. Another option is the bus from Bright. Bright is a good place to stay if you want to do Hotham one day and Falls the next as they are both equal distances away from Bright.