This plugin is great. I used it to sell tickets a music performance on my site. This is the first time I have sold anything online and the setup instructions were straight forward.
The only fees that you will encounter are from paypal (i.e., unavoidable). Other services will charge an additional premium which will dig into profits.
The not so good:
It would be nice to collect ticket holder information prior to payment through paypal. Too many people didn't fill it out after purchasing and we had to resort to "email@example.com, party of X" at the door instead of having individual names to check off.
This plugin doesn't provide 'print out' tickets. People who pay for things want to have something in their hand for the money they spend (electronic QR code login at events would be great too)