SOUTHPAWAMI  I personally use it for instant messaging. I use it for instant messaging because it does AIM, Yahoo, and some others. Yahoo Messenger for mac doesn't have photo sharing, so there's no other reason to use something else besides Adium. I've never had a problem using Gizmo for voice chat, though Skype usually works a little better in sound quality.   
(Version 4.0.0.266)

ANDYCHRIST  F***ers wiped out my account balance and now don't recognize my registered email address, though they keep sending me spam there. Grrr...  
(Version 4.0.0.266)

GMAX  Gizmo5 (which is actually version 4.0... duh!) fails to launch after updating to 10.5.5.  
(Version 4.0.0.266)

HALODEMO002  not bad, just needs a little more put into it  
(Version 4.0.0.266)

TRAHE  Well the rating is bad, bcs i would recommend anyone to stik with the old 3.1.2 version, even so it has no video function, stability and most of all the ACF function works.

To explain:

ACF = All CAlls Free, which means the buddies on your list may become ACF members, and then you are able to call landline/or even mobile phone of those for free.

The new version seems to get nuts on this feature, it marks almost everyone as active ACF (curiously some are marked inanctive ACF (so i can use this plan in the old version).

Which means in fact :

The new version shows peoples number like you are able to call for free, but EVERY CALL you do is charged! Even the ones previously used to be free!

This is a big step backwards most annoyingly cannot rely anymore on the ACF Status.

Even so it might make your acount settings confused!

So if you like the ACF plan of Gizmo you better do not touch this Version !

PRO : Well it has no video and like always Computer to Computer is free anyway

CONTRA : Using it for mobile / landline you never know , if you are charged or not (well most of the times you are charged)  
(Version 4.0.0.260)

NWS  I needed an extra number for incoming calls and the occasional outgoing call and Gizmo works perfectly with my Macs. I've had it with the high costs of traditional, old tech phone companies.

The Gizmo interface could be a little sleeker and more compact but it's not a problem.

I wasn't keen on becoming a supernode for Skype, dealing with Euros or payment issues (I had them).

I waited forever for Google's GrandCentral and for iChat to be something more than AIM.

Overall, a fine program.  
(Version 4.0.0.258)

THREEDEE912  It does have that Mac-ish feel, but there is definitely some clutter.  
(Version 2.0.3.195)

APPLEDOGX  Works, but after the free credit, it let me buy credit, then sent me an email saying it was refunded. Seems to have bias about not letting some places, like whre I live, buy credit. Would save me money, but if you can't buy credits, it is useless.  
(Version 2.0.0.161)

TOMIS  Gizmo has better feedback cancelation than Skype. They both accomplish the basic VOIP functionality well.

Gizmo's Call-Out within the US is 1¢ while Skype's is 2¢ normally (Skype's call out is free for the rest of the year).

Considering the features of Skype and Gizmo are essentially the same, I found Gizmo's interface to be cluttered and confusing. I also find Skype's interface to be cluttered, but Gizmo's is far worse.

The better solution would be for Skype and Gizmo to both contract with Apple to add support for their protocols into iChat so we don't have to suffer with these bad Windows-ported interfaces.

Overall I'd say Gizmo has a better feature set. But the interface is so horrible that even Skype is better in comparison.  
(Version 2.0.0.161)

DOC RENAUD  I live in France but have a lot of friends in Canada since I use to lived there for 10 years. When I use Gizmo for France to France call, the soud is garbled. But calling from France to Canada sounds perfect, even if sometimes it takes about 10 atempts to get the line (The number you dialed is not valid...) And I know it is.

Anyway, this app saved me a lot of bucks on international calls.  
(Version 2.0.0.158)