.152 hasn't been the best OS for me yet. Honestly .133 gave me the fewest troubles, but I'll give it another week or so to see if .165 or better makes it to "market".
For what it's worth John my wife's 8220 has been able to hold a UMA call at the same time as my 8320 and my 8900 when I tested it. Other then that we're not both on the phone at the same time often, but I am pretty sure I was on .133 when I tested it.