To me, if you live in the USA there really isn't much advantage to Skype or Gizmo unless you're calling internationally or are very restricted to the number of cell minutes you have.

I got rid of my landline and cell phone and just use Gizmo exclusively. Rarely have problems with it unless I have a weak wifi signal.

same here, I will install it just to check it out and then will be out of my n800 after 3 days...
I was happy for the webcam on n800 when it came out, but so far that camera has no use at all. Skype with video support will be great, without video... i will use my cell phone (at least I can send pictures).

I use GIZMO on 770 with SIP-voipstunt. I can call landline (nearly for free ...) and any SIP-compatible service (<> Skype ...).
A NEW version came 2 days ago for the 770 .

Skype

By using Gizmo and GrandCentral (free local phone number) anyone back home (US) can call me for free when I am traveling in Europe. So far the quality of the calls have been very good.

Couple of things about Gizmo and Skype...

Unfortunatly the reason SIP is not more popular is because it's is ridden with problems. I've spent months trying out various clients including Gizmo and Wengo on three different routers. Port forwarding, STUN servers, RTP, UDP... are you kidding me! Don't get me started on trying to call someone on another SIP provider. I say SIP was dead before it started.

Skype in all it's evilnes, firewall or no firewall, just works. Period. You don't need to be sysadmin to set it up. Windows, Mac, Linux.

So, again, open protocols are great concept if protocol is good. In SIPs case, protocol is piece of crap, so way support it?

And another thing. If you talk to a lot of people in Europe, chances are they use Skype.

There, I said it.

It seems I must be lucky then because Gizmo works like a charm for me in Europe without doing anything special.

I have no doubt it can work, and Gizmo is nice piece of software even on N800, Wengo is even better with video support. But for mass adoption, it's not it! I really hate to be categorical, but until they fix the problems with protocol, SIP is not going anywhere.

I brought my N800 to a week-long trip to Greece in early May. I have plenty of SkypeOut credit left but Skype had not been released for the N800 so I purchased some Gizmo credit for calling back my folks back in Beijing, China. In the only few chances that I got connected to a public wi-fi hotspot, the PC-to-phone quality of service of Gizmo was so bad that it was painful. With SkypeOut I almost always get good call quality but with Gizmo (at least the few times I tried from Athens, Greece) I could get the phone connected about one out of ten times. All other tries I was just thrown back at the dialer screen, without even hearing the phone ring on the other end. Of the one or two times I was able to connect, the call quality was okay but who can stand trying to call home for a dozen times and being able to hook up twice? Maybe it was bad luck but the day I can get my hands on Skype on the N800 I will throw Gizmo out of the window along with the leftover credit balance. That's just me and your mileage may vary.

KS

First off SIP needs less administration. Its a standard protocol supported by many devices and firewalls. Most public places allow SIP protocol to pass through thier firewalls. if your having issues at home get a real firewall/router. D-Link Gamer /wireless 1Gb router is the best bang for everthing. Passing encrypted packets on time is no easy thing for any router. Dich the junk Linksys/netgear routers and get a dlink. They dont buckle under voip calls. I have had zero issues with gizmoproject and its worth every penny. The only reason i want skype is because it makes the N800 more usefull to some people and that makes people build more application.