you have full control of the data!
that's the main thing i see here.
everyone know that google uses your emails to show you ad you might click on, every one knows that google doesn't forget anything...
don't get me wrong, i also use gmail since the beta began, because it has the best webinterface for emails i've ever seen,
but as soon as i find an alternative, i will close my gmail account.
woth opengoo you have the control of the data, you can delete it and it will be deleted...
opengoo is on th ebest way to become an alternative, and i really hope it will replace my gmail account one day...
ah.. and opengoo is ad free (well, gmail is, too, if you have adblock and noscript XD )