Update 2010: While the price has gone up with fees and such the service has too. Now all the countries I ever call are included in the unlimited plan. For me still a clear winner...
Update 2009: Still going strong - reduced costs somewhat by switching to annual prepay (saving 20%). Still 100% landline replacement without issues for me.
Update 2007: Still going strong - the additional taxes and fees are not so great but it remains the most solid provider - and in my case a 100% landline replacement...
Update 2006: Nothing really new - still 100% solid reliable ability to make and receive calls.
Update 2005: Now in my third year of Vonage I am still very happy with the service. It's a true POTS replacement for me (with stable Broadband) with almost no outages... Can't beat that!
I got Vonage over a year ago with one line and started using it for outgoing only. I never had any real trouble and the few times I needed to contact customer support I got through to someone in reasonable time or my emails prompted action in reasonable time. I added a second line and hunt group to my Vonage account in Mayof 2003 and got completely rid of Verizon. My Verizon bill for the two lines (including Caller ID on both and Call Intercept because of the high amount of marketing calls) + LD + International was >$100 each month. Now the bare service is $32 including all fees etc. for two lines with much more features than I had before and about $50 including my international calls... Not bad to save at least 50%. I have a very stable Internet connection and can count the times I had call troubles in this 1+ year on one hand....