Summary: I ordered the Siemens as a replacement for an aging Panasonic system that we needed more handsets for anyway. Prior to buying the Siemens, I'd fooled around with VoIP using a Sipura ATA (SPA-3000), and while it was decent, the configuration practically required a technical certification to decipher and properly program all on its own.
Summary: I have used the phone with two different VOIP services and it worked with both. The sound is better that my old land line phone. It has a color display but not much can be done with the colors. It would have been nice if I could upload my contacts pictures. The wireless range is very good, throughout the house and outside. Supporting a land line works very well and you can choose which service to make calls on. Each handset an be configured as to which lines ring.
Summary: This is my first IP phone and I am really amazed, it was easy to set up and works smoothly with several VoIP accounts - the biggest issue were the router settings. Also the sound quality is great, I was asked twice if I would be in town even though I was in a different continent... While the main functions are working really nicely and the phone is easy to use (like a normal landline phone), the software could need some improvements - biggest complaint I have is there...
Summary: I was looking for a phone that supports multiple VOIP accounts and I am happy with my decision. The only thing I am missing, compared to my analog Panasonic DECT phone, is the talking Caller ID. But you can assign different ring tones per phone book entry, so that makes up for it. The only problem is that I can not register my Panasonic DECT phones at the Siemens base, but that might be a problem of the Panasonic phones, as they don't ask for a password.