Nearly all of the functionality we talk about in the SlideRocket product tour is available in the current private beta release today. The only exception is the PowerPoint import (which will be online next week) and the community features.
Lots of cool features that we don't advertise yet will be released in the coming months including a bunch of new effects, plugins and animations, support for H.264 video, offline support and a full-suite of enterprise features.
I did a quick test to see how the text looked in Flex using FlashType rendering and I think it's definitely better than WPF or Flash (i only tried verdana at 9pt though).