I use the PayPal labels, which is actually the USPS Click-n-Ship with an eBay and PayPal logo at top and bottom, repectively. I've been using PayPal shipping since last Fall.
The major advantage to the PayPal version is fill-in of buyer details and method (read that as fast). It does the Buyer's address and knows the shipping method selected by buyer, when done with eBay checkout. Auctiva's checkout was having a problem getting correct shipping method for the PayPal label, but not sure if the problem continues. It certainly saved time to not have to fill-in or copy and paste address, which can have transcription errors. It's also FULLY TRACKED in the PayPal system, so THEY KNOW when you shipped, delivery confirmation, etc. I've never had a lost (not delivered) item dispute, but knowing PayPal already has the details should certainly help with any dispute resolution or charge-back. PayPal also gives you warnings and tips on shipping method and tracking, e.g. use Signature Confirmation over certain $ value on item for protection under policy.
There are things I don't like about PayPal, but the shipping labels ain't one of them.
It's not like you really have to sign-up for it. Try it and see if you like it, especially if you already have the half-page shipping labels. I use the USPS as a fall-back for problem checkouts or combined ships that fall through the eBay cracks.
Oh..and you can turn-off doing the full-page for the labels to save on labels. There is a setting for that method in label setup.
Danno