I've made 8-10% per year (defaults included) for the past 2 years on lending club. There are investment limits based on your income that you legally have to follow. I believe its 5% of your income/assets max. They don't confirm your income/assets but there are regulations related to it.

It also takes work to liquidate quickly. So if not selling notes on a second market you're locked into your investments for up to 5 years.