They are Android based IIRC. They look sharp and the pricing isn't bad. I think @scottalanmiller had gotten one to test with previously?
Yeah I think he did but didn't like them. Scott prefers Sangoma and Snom if I remember correctly.
Our experience with Grandstream is that they were insanely cheap and worked okay and died often. If you need something that is going to get beat up and won't last long anyway or is super likely to be stolen, they are great. But over time, you don't save money and they are very obviously a cheaper phone. So it's not like they were "bad", but once Yealink got withing 20% of their price, their point was really gone.