One tip in case you haven't heard it already: Auctiva's Checkout doesn't allow for combined invoices. So if you like to be able to combine shipping for your customers, you might want to go in and turn Auctiva's Checkout off and continue to use eBay's. (You can, however, still buy insurance through Auctiva if you so choose even though Checkout is turned off.)
Personally, I love Auctiva and after the server move tonight it should be even better.