We have Ooma Office. I have an AT&T 2 line phone (one line is Ooma and the other is personal). It connects to a Bluetooth headset and has a speakerphone.
I am finding sporadic problems with being able to access other phone systems (of other companies) automated attendants when using the handset or my headset (speakerphone seems to work). It seems unresponsive - sometimes but not all times.
Also, I am finding it hard to “hang up” on these systems – I sometimes lift handset and hang up but I get called back by Ooma or I press flash (that doesn’t do it) or press Bluetooth button. Nothing hangs up all of the time.