Excellent plugin! It does everything I could have wanted it to do that I couldn't find in any other similar plugin without all the "oh, you want it to work? That's $xx/month" nonsense. Of especial importance was the fact that I had over 200,000 invoices already in my Quickbooks. I couldn't find a plugin that would take that into account. This one did. The way it functions to sync up the invoice numbers is just fantastic and took a big load off our bookkeeper who now loves me again.
Additionally the very responsive support I've received after the fact and the eagerness to incorporate suggestions have made this even more awesome. I have had a few kicks at this can and this has definitely been the best one by a long shot.