Former AT&T Calvantage CustomerI've been with AT&T Callvantage for at least two years, and only changed because they were canceling their service. This review will cover only the transition from AT&T, since quite frankly I haven't been with Phone Power long enough to judge reliabilty. My main concern was that I was transferring two different phone numbers with AT&T, and they were important numbers not to loose. My fear was that the primary number would be transferred and the secondary number lost. Since the wife uses the secondary number, that would have been very bad for me! To avoid any problems I placed the order over the phone, instead of on-line. The process was quick and courteous, and I have no complaints about that whatsoever. First rate. I then started to receive a serious of emails, a total of at least five, keeping me advised as to the progress. I became concerned when one of the follow up emails didn't mention the second phone number. After waiting several hours for another email mentioning that number, I contacted customer service. The first attempt to reach them by phone resulted in a wait, so I sent an email instead. It was answered a short time later indicating everything was okay, and after that I received the second email I was waiting for. I'm not sure there was a mistake on the second number, but their process kept me well informed and perhaps helped prevent one. A bit later the VOIP device arrived. It's rather tiny compared to other VOID devices I've seen, but I plugged it in and everything fired up fine. The device claims it takes up to 15 minutes to boot the first time, but I didn't check that. It did pass through traffic to my router almost immediately. A few hours later and I checked the two phone lines, and they both worked (outgoing only at that point). I also set up the various service settings using the website, so that when the service was transferred, everything would be operational. When the transfer of service day did arrive, it happened right on schedule and without incident. In the morning everything was going through AT&T, and by noon everything was going through Phone Power. Call quality seems just as good as AT&T, which is rather good. There are two things I'm very happy with in the change over. First, the Phone Power website is much better than what AT&T's site was. Second, when I'm answering the phone I no longer have to hit "1" to have it know that's the line I want to pick up on. That was perhaps something AT&T did only when you had it ring multiple phones simultaneously, but since that's how I always have it ring, that was annoying. Anyway, so far, soooo good. Very happy with the changeover.