Installed this on a WordPress 3.1 site for my upcoming wedding. Installed just fine, setup was easy, and the documentation was good. You have to pay $13.95 to register the plugin and get an activation key, and Paypal will take a fee from each transaction (about 3%), but it works great!
The look can be modified using a style sheet, and setting up the Paypal end was pretty straight-forward.
Some of our guests are older and less experienced with computers, and they managed to send us gifts easily.
I really liked being able to link to descriptions of the items you're requesting, and being able to break up the prices into whatever blocks you want.