For $29/mo, we provide access to advanced level technicians who will answer your questions on any Macbook board related matter to the best of their knowledge promptly & walk you through how to solve your problem so you can deliver a working board to your customer.
I'm using RepairShopr. Before I was doing Apple repair full time, my day job was actually in (retail oriented) POS software sales. RepairShopr has some nice features that some of the "big" ones don't have, but also lacks some customizability I crave (but most cloud software does, let's be honest).
One big feature for me is the ability to spread freight costs amongst received product. Being in Canada, shipping and exchange are a HUGE increase over the "base price" in USD.
Integration with WooCommerce is also really nice. Updates in real time.