I hae a voip line and a land line. I'm not giving up my land line ..quality is spotty. With DSL it's awful when I'm trying to do more than one thing on the computer. Might be better with cable internet.
Yeah, the key is the upload speed. You need a minimum of 80 Kbps. I was having occasional problems, but did some tricks to port settings on the router and it's been great ever since. I really like the call blocking features. That makes it worthwhile.
I'm a happy VoIP user with DSL Internet service. My VoIP service wasn't good or solid until I upgraded my Linksys firewall/router firmware to include Quality of Service functionality. Now that I've set the Linksys to give priority to the VoIP adapter it's great. No more echoes or lost dial tones.
During the Big Blackout in the summer of 2003 - all my friends who only had cell phones had to come to my house to make phone calls. The landlines still worked - the cell phones didn't. Until I know there will never be another blackout - I'm not giving up my landline.