The Boy Genius has published a comparison between the Blackberry 8800 and the Blackberry 8300. In the article you can see several pictures of the two devices side by side. The 8300 seems to come out on top as TBG notes "the trackball sits much lower in the device as it does with the 8800 which is great. It feels right now. Remember I told everyone there was the Pearl, then the 8800, then 'RIM's perfect device?' This could be it!"

Check out the pictures for yourself. The 8300 seems to be a better size.