First i'm sorry for mention the others, but its my right to compare the providers
now i have question
what is your offer behind user registration that others can't?
bitzland you're already using the other system and you are happy with it.. so stick to it, and don't come here, I will be happy.
Mexicantarget is making a system FOR HIMSELF first.. so he doesn't care about your needs or anything.
When faucethub will be released, you'll will be able to try it if you want and see if it does the job for YOUR needs..