[fbuilesv]

This is just one data point: I was planning to use a .io domain for an online fashion store. I talked to several customers and asked how they felt about a domain ending in .io. ~30% of them thought it looked weird or plain "fishy".

If you're trying to sell something directly to people (especially physical good or stuff where you don't get a trial) I'd try to stay away from them. They seem handy for URL shorteners and techie stuff.