Well, while the APR are huge, Wonga at least provides a lot of info on the APR, at..
http://www.wonga.com/money/is-this-apr-expensive
They explain that if other comapnies were forced to quote yearly rates then you'd be shocked too... for example
rent a video = 1,000 per year,
rent a taxi cab = 876,000 per year
rent a hotel room = 90,000 year
(not my figures, from Wonga)
They also claim that the APR system isn't suitable for a short term loan product, as the interest is compounded in the calculation, whereas with the real product the money is paid back quickly, before the interest compounds. They explain that the APR increases as the term of loan shortens, leading to huge APRs on short term loans.
Is a pawn shop better value?, or a loan shark?
The companies provide a short term loan service, i.e 100 for 5 days, repay 110.. or 100 for 15 days, repay 121. This might suit some people who need to pay something. I agree that if used unwisely then people will get into trouble, and perhaps these companies do prey on people without much choice or financial wherewithall.. but caveat emptor applies.