We use this at work for talking to customers and it works fine, but note that they use Twilio under the hood IIRC. Also their SPA app is what you'd expect from

We use this at work for talking to customers and it works fine, but note that they use Twilio under the hood IIRC. Also their SPA app is what you'd expect from JavaScript apps—buggy and prone to slowness once it reaches a certain scale.