Yes, we have had a good experience with Shipworks so far. We have been using it with X-cart for 3 months now without a single problem.
The integration was surprisingly easy. It was just a matter of uploading a single file, provided by the Shipworks website, to the X-cart admin directory.
We have found Shipworks to be an excellent offline order and customer manager. We were already using it for our eBay stores as well, so it is nice to have everything on one screen when fulfilling orders and handling customer emails.
I highly recommend it for small to medium volume sellers.