I've been using FSB for 6 months now and I am pretty happy with it. I found out about it while looking for a simple way to promote Amazon.com's products with my affiliate link.
I found it easy and simple to work with and only took me a few hours to have a full featured store up and running. The coolest thing for me is their licensing, it is very flexible so I can continue to build more similar websites and generate passive income from it.
I am sure I can make at least 1 really good well polished website with FSB every month, that would be 12 in a year's period, all generating solid 200 to 300 dollars in revenue.
I would definetely recommend it.