Does anyone use Bobsled?
 

Bobsled is a free app for iOS & Android that permits free US VOIP calls. Has anyone tried it? Comments? Observations?

I have it on my phone. It seems to work ok. I haven't tried to use it on any networks which block VOIP and the caller-id it gives is generic.

Have you compared it with other apps, like Talkatone (a Google Voice app for iPhone)? I'm curious if it has any particular advantages.

It is comparable to Talkatone basic (but no incoming calls or text messages). If you pay for Talkatone's premium codecs, Talkatone is better.