I love mine! It's only as good as your broadband connection so any issues will interfer with your quality.
That said, I don't even have mine connected to my computer any longer. I have it configured to send me an email then I check my VM and see if it's a call I want to return with my cell phone or not. It's a cheap way to avoid telemarketers for those times when you "have" to give out a phone number.
I like it because I can have a local number in a specific area.