Ask HN: What Virtual PBX service do you use?

I'm in the US, and my only must-have features are find-me/follow-me, unlimited numbers on a call block blacklist (the one missing feature on my current provider that is driving me to look for a new provider), incoming fax, and can migrate an existing toll-free number. I'm not price sensitive, I'm willing to pay for quality of service. Not having legions of pissed-off customers posting horror stories of billing and support issues to Yelp and other places on the Web would be nice, but it seems to be the fate of every company in the telecomm industry to raise the ire of a significant proportion of their customer base.