Well, I got suckered in again. I splashed out and purchased one of the Cisco 7961 VoIP phones. As always, it's very nice gear - that is when it works. Cisco have been very smart with this. They say that their SIP firmware is RFC compliant and should work with any VoIP server - however, sadly, there are that many bugs that stop it from working properly, I don't even know where to start listing them here.
It's a really sad day when I can say that my $150 Sipura phone that is 3 years old is more reliable than a $500 Cisco phone. While it does take calls (if you look at it right), the message waiting indicator (MWI) doesn't work, the phone randomly crashes, the configuration files are not documented at all, the phone randomly drops calls, it randomly unregisters lines, and becomes very unstable after about 12 hours of being powered on - meaning you need to reboot it around twice a day.
To add insult to injury, I have been trying for 3 weeks to purchase a smartnet contract to allow me access to newer software for these phones, however 1) Cisco won't sell them direct, and 2) none of their resellers are interested in selling me a smartnet contract.
At least the phones look nice - because it still looks like an impressive paperweight.