Those of you still having trouble with getting PayPal working well in WooCommerce may want to take a look at PayPal for WooCommerce, a plugin I just launched.
I'm a certified PayPal developer and an official PayPal partner. I've been integrating their stuff for years, and I just wasn't happy with the available options to get PayPal running on WooCommerce, so I built this and launched it as a stand-alone plugin.
It currently works with Express Checkout and Payments Pro, but I will be adding Recurring Billing, Adaptive Payments, Invoicing, and more in the coming months.