It might be not too honest for me to write about a competing application (I belong to a volunteer Aston support/design group), but all written below is my personal opinion. In other words, here I speak for myself as a user.
According to the official homepage , Talisman is a "desktop alternative and shell-replacement for Windows 9x
The thing, that amaze most people, new to the Talisman is a large number of beautiful themes. Actually I think, that Talisman is clearly one of the most beautiful shell replacement applications, available today. A theme can contain buttons, icons and plugins, which is normal for most modern shells. But unlike most of them Talisman can use HTML elements inside themes. That brings designers some really interesting features. For example, there are themes with dynamic content, like web pages and even games. Designers can easily guess, how much freedom it gives: flash animation, dynamic menus, even 3D graphics via VRML...
The rest is quite typical: multistate buttons, plugins, hotkeys for some actions... Combining all available eements it's possible to make some really interesting stuff, so skinners, who're looking for a good way to apply their imagination should take a look.
But like all the good feelings one's freedom euphoria has to pass as soon as you try to do actual work. Even in it's latest builds Talisman is buggy (though now it's much better, than a year before). For example, you can try loading a theme and finally stay with an empty screen and a lonely Taskbar with few flashing buttons. Or right in the middle of your work it just crashes without any reason. Another annoying "feature" is Talisman's resource usage. Talisman is slow. Sometimes incredibly slow (laters versions trend to work faster). From one side this is a retribution for embedded HTML elements, from another - numerous design flaws.
Overall Talisman, even in its latest incarnations is too crude for the daily use. Its performance and stability improve, but too slowly. It might be a good "one button" interface for media centers or libraries (where you don't change themes twice a day), but it's definitely not intended (yet) for active use.
Talisman Desktop is the main application, developped by Lighttek, Russian software company specialized on Windows customization software; other interesting Lighttek products are: Alteros and Icontoy.