I have caller id ($10 month AT & T) and digital answering system on the panasonic, and the voicemail is set to answer after the Ooma is.
I am not receiving any Ooma voicemail, but I do get some messages on the Panasonic, but not always.
Very large percentage of call are showing as UNKNOWN, esp. with mobiles. This is not the case if the Telo is taken off.