speed:
jnimmo: personally I would avoid Panasonic IP phones like the plague
From my own experience (just as phones for home) I would agree. I had a TGP500 and found it far less flexible than the couple of Siemens Gigaset's I had, and I quickly ditched it and went back to Siemens - which I find great. But that was a couple of years back so maybe they are better now.
Biggest complaint was how hard it was to dial out from a different line/registration - which is super easy on the Siemens handsets.