We had the IP300’s at first but the speaker phone was not full duplex and that annoyed people but the sound was good with it. And yes the message waititng indication was a problem too. I then got a few SNOM’s and the setup was so easy but I could never get the sound right - had endless problems with using Planatronics headsets with them. But we got the IP501’s now and I have to vow that the sound is even superior to the IP300. I guess it is a combination of things.
But the echoing seems to be a persisting problem with IP phones - they all have some degree of echoing.
Anyway side question: I seems to get frame slipping - the telco compamy told me so - unless I put an Adtran TSU120 between Asterisk and the telco. I have played with the LBO and tried different settings for different line distances but can’t get it solved. So after about a day or two all channels will just become unavailable and they have to reset the telco switch - you had any problems like that?