Yes, I've used them for the last year and their software is horrid and can barely be used to make phone calls without crashing frequently. Also, their support is quite crap.

That said, they pushed out an update about 3-4 months ago that improved stability a lot.

I’ve had them as a voip provider for about 10 years. We have a landline number that my family has had forever parked with them with a flat annual rate. I’d rate them as medium, there are some rare issues but it mostly works well. Residential voip seems like it’s dead though, I wouldn’t be surprised if they sunset the service.

I use both 8x8 and Nextiva. 8x8 is acceptable, but Nextiva has better sound quality.

We used them years ago for VoIP services but subsequently switched to Vitelity.