I have Vonage. Just moved and decided that I wanted to have my home phone as cheap as possible, since I don't use it much. So far so good with the service, it was super easy to set up and get working and the calls are clear. The caller ID works just fine as far as I can tell. It even works on my Audrey that I have hooked up to it.

Advantages:
1. $26/month gets you all the calls you need to make
2. All the features too: call waiting, voicemail (online), you can even get an email telling you that you have a voicemail
3. Take your phone number with you if you move (I couldn't care less though)
4. You don't have to pay Verizon a damn thing.

Disadvantages:
1. No electricity = no phone
2. Your crappy internet provider goes down, so does your phone.
3. Questionable 911 service. I say questionable because you have to call Vonage to tell them your physical address so that when you call 911 they can tell the cops where to find your dead body. (or something like that)

Oh and about the $30 start up cost...

Go here and it will sign you up as a referral and you get your second month of service for free (I think. That's how I signed up)