There is so much potential available to this extension, but it just doesn't get it done and when you combine that with the outrageously high price they charge, it is just highway robbery.
As others have stated, the template designs are really poor. That being said, they are better then most - because the others are horrendous. That is probably why the RSJoomla team hasn't improved them, which is sad.
No ability to create tags to sort events, they allow multiple categories, but won't let you sort of them once you do. They calendar won't display the color codes correctly if you use multiple categories.
No ability to use smarty code to fix the horrible php coding they use.
No integration with sh404SEF or any other SEF. End up with terrible URL's
The potential here is tantalizing, but at the end of the day, I wouldn't recommend it.