Hi Mike D, I find the Auctiva customisable storefront very good especially as it eliminates the need for eBay gallery pics and the associated fees when only using eBay's 'store front'.
You say above that "The Auctiva store is not necessarily a replacement for your eBay store" but as I understand it the Auctiva store cannot be an replacement because you do not provide the 'venue' aspect, so therefore it is not standalone.
Please correct me if I have mis-understood.