Michael Robertson is the master of hype. No one can do it better, and he's so, so, good at it. Now he's trying to spin why a smaller client, Gizmo, is better than Skype because the file size is less.
Now we all know that in some cases Size Matters, but what I think really what is at work is that Robertson is trying to compare performance versus coding bloat.
First Skype does IM and file transfer. Gizmo doesn't. That said, my Gizmo to Gizmo or Gizmo to SIP calls have been perfect. Skype of course can't terminate on SIP endpoints without going through a PSTN gateway as of now, but I'm sure someone will figure that out. Lastly, Gizmo is also about being an onramp to SipPhone's network, and just happens to be able to do what Skype does, allow people to talk, but actually provides a more complete experience.
What Robertson is really doing is drawing comparisons to Skype so Gizmo is viewed as a competitive product, rather than showing how it's better or different. In marketing, it's what makes you different that matters. For Michael, it's only really about how he can increase the value of his ventures that matters, as everything is geared around doing just that, which is why I like him as an entrepreneur.