I had NO issues installing the upgrade. It worked flawlessly.
Also now being able to receive an email that shows me exactly who registered and for which level and what class for each registration instead of a simple link saying someone registered is one of the components I have been waiting for. The only thing left I would like to see is the ability to easily move a person from one registration to another. That is not enough to make me switch to any other extension out there. I have used most of the free ones and this one is WELL worth the price.