The recent upgrade that increases the number of button options from 2 to 9 is critical. I simply installed the newest version, disabled the old one and voila, beautiful!
The test mode is very handy. Create a PayPal Sandbox account, make sample purchases on your website and see the email messages received by both the seller and the purchaser.
The documentation is terrific, you can quickly skim to find what you need and be up and running in minutes.
Nice PayPal Button makes PayPal easy, thanks!