I have used zopa.com to lend money. Pretty easy but the returns are not great. Its worked out at about 3% over the last 8 months so I may be looking to shift the money elsewhere for a slight higher return come May
I used Prosper last year, same with JamesNorth101, returns was about 5% after loan loses and their high fees. Wasnt worth it to return to it. I can get better yields with high paying stock dividends.
I've tried Lending club last year. IMHO they have big expectations on your credit score to give you a rate that is higher than what you can get from Capital One for example. So I just moved to private investor.