Right now I'm annoyed by Ubnt's communication. I used to like their no-bullshit specs like "this is product X and it does Y", but the whole new Unifi "SDN" product line is a mystery to me. What's the difference between the UniFi Security Gateway and a EdgeRouter? Last time I looked, the Unifi controller was a piece of software to configure the APs which doesn't have to be running all the time, now it's a SDN controller with included PBX? There is no "one size fits all" PBX. 

Regarding the phones, the data sheet is a joke as well. Nothing about supported phone features, which makes me suspect there's hardly anything there.

Encryption? Auto-Answer? 3rd Party Provisioning? Multiline? BLF? Presence? Pickup? Callerid/Connectedline display/update? Picture CLIP? LDAP? Ringtones? MWI? Hold/Transfer? DND? uaCSTA? Push messages? Hot Desking? Answered elsewhere?

We don't know. It *might* be an interesting enterprise phone, but I presume it's not there yet or it's not even trying to be one.