I tried to become an affiliate with Extabit about a year back but it seemed to be locked out for me (maybe because I'm an American).
But I did have a downloader account which I used to download several Terabytes worth of Siterips over the course of a few months. So unfortunately I can say its very easy for someone to rip you off on a massive scale if you're using them as they don't appear to have any strict bandwidth usage caps.
I've long since cancelled by premium account with them and from time to time when I'm looking for something obscure I'll find that its only available on Extabit. From a regular Joe Blow downloader's perspective it would be highly unlikely that I'd purchase a premium from them as there are too many spam popups, annoying CAPTCHAs, and deceiving interfaces for files which were deleted.
There is a balance that is nice with a file host, inconvenience the user enough to make them purchase a premium. Extabit's balance in my opinion is way out of whack and I'm glad that I never wasted my time being an affiliate of theirs.