SHOULD I GET SKYPE OR VONAGE TO REPLACE MY LANDLINE?

Skype is a good long distance alternative. However, I would not recommend Skype as a “home phone replacement” alternative because of the lack of 911 access.
Vonage is a better alternative to Skype as “home phone replacement” service because they do provide 911 access. And, their VoIP boxes connect directly to your Internet modem – thus you do not require a PC to be running to get VoIP phone service, like Skype does.
Personally, I think Ooma may be the best choice of the three options you are considering for home phone replacement service. They do provide 911 service. Their VoIP adapter plugs directly into Internet modem and does not require a PC to be running. Except for the upfront cost of purchasing the Ooma VoIP box, I think in the long run it will end up being much cheaper than Vonage.

I had vonage way back when the whole VoIP thing started… I never had any problems with them when I was a customer.. but I haven’t used there service in years…
lately there have been many people on here and other places voicing complaints about vonage service. some people think that vonage may go the way of sunrocket soon…
I used skype as a land line replacement service with a D-Link DPH-50U so that I could still use my standard telephone, however, this method requires your PC to remain on all the time, unlike some of the other phones that you could purchace made for skype that just need an internet connection. in this case magic jack would be a better option if you do not mind leaving your PC on, and being able to use the phone that you currently have… also I was not satisfied with the QoS of skype, and the fact that you had to dial + (or double 00) before dialing every number…
ooma IMO seemed like a risk, because there is only one charge for “lifetime” of service.. it would be a gamble that the company was still around long enough for you to break even. BUT they have been gaining momentum, increasing there customer base, and lowered there price, so it may be an option that I attempt to trial in the future…
the best QoS land line replacement would be the service provided by your cable or internet provider..
ooma seems like a great service, but it is basically a p2p telephone service, they rely on at least a good portion of there customers to maintain land line service, and keep there land line service connected to there ooma box, so when someone makes a call from ooma, it is routed to someone else who has ooma, and dials out on the land line service closest to the destination…

I had excellent service with Vonage meaning customer service and quality of calls (sending and receiving).

I would recommend using Skype.