Of course, the biggest change is that the Gemini ditches the track ball for an optical mouse. This could be a great decision by RIM, as I know at least ten people who have had to repair the track ball in their BlackBerry. It's not about the build quality or anything, but the chances of failure are higher with the more moving pieces you have. I tested an optical mouse on a Samsung Innov8 a few months ago, and it's a solid navigation system once you've gotten used to it.
It looks like a really nice member of the BlackBerry family, but it appears that it won't have 3G connectivity, which is a bummer. We may see this sooner than you'd think too, as there are rumors RIM will announce a new device or two next week in conjunction with its Wireless Enterprise Symposium.
The good guys at CrackBerry have a few more pictures of the Gemeni, as well as some in-depth analysis.
(Photo Credit: CrackBerry)