Hey, it might not win any awards, but I think it will be fun for a casual roleplay. I've done some vampire stuff before, and I felt like android would provide an interesting contrast. Vampires tend to be unusually old and rather traditional. The androids will be cutting edge and novel. There's also the magic vs technology angle. And how does the predatory relationship between the underworld and humanity change when a third element is introduced? 

It would also just make for some cool action scenes. :)