We use StoneEdge Order manager, and they integrate with Blackthorne. Ever since Blackthorne moved to offering a SQL version, the StoneEdge integration has been rock-solid. Blackthorne is a great program, and integrating with Blackthorne rather than eBay directly minimizes all the issues with eBay API problems. We actually moved from Blackthorne ($30/month) to ChannelAdvisor ($1000+ / month) and hated every minute with ChannelAdvisor and moved back to Blackthorne.
Here are some key points to a solid integration:
Blackthorne offers a ProductSKU field which you can use to match to the IS item ID - importing orders, dealing with payments, and status updates is all we need.
There is no need to launch auctions from IS because your eBay ads should be different from your webstore descriptions.
We can train just one person to deal with launching auctions through Blackthorne, but after the order is complete, we would like everything done through IS, so payment processing and refunds should be handled via IS. This means that Paypal integration is necessary. I can probably get Paypal to make resources available for an integration with IS, but I don't know who to talk to at IS to get this done.
There are two ways you can handle imports - the easy way is to only import orders that are paid for....
The harder way is to import all completed auctions and then update the payment status automatically as payments come in. You can use Blackthorne to check for new Paypal payments - just check for status changes of payment on all previously imported orders (that haven't yet been marked as paid.) We prefer this method because we can apply check, cash, and money order payments through IS.
Various status updates to Blackthorne would be necessary. Most important: item shipped.
PLEASE CONSIDER THIS INTEGRATION! It is a huge missing piece of most ERP systems. Netsuite is about the only company that has an integrated component, and we are considering them on account of this feature alone (despite all the horror stories). Bill, I hope you will chime in with a response.