The most functional part of SolidCommerce is convincing you to sign on. You will notice, however, that they won't let you run a demo of the system or use a dummy log-in to look around.
The platform is broken in many regards. Order systems don't work correctly. Shipping software is below second-rate. Constant glitches and bugs makes working through the system frustrating. We can't even stay logged in for fifteen minutes without getting kicked out. In fact, this is being written while we get logged out every thirty seconds. Expect to spend as much time learning the work-arounds as you do with your daily business for a few weeks or months.
Get ready to pay them to beta test! They'll tell you the running versions of Inventory/Orders/Shipping systems are "No Longer Supported" because they are being replaced. The replacements have been in beta testing for YEARS and those aren't supported because betas are a "Work in Progress".
Account managers get swapped out every 3 months or so. Anything ongoing or outstanding is designed to be forgotten about. Your frustration and need to take care of your own problems is what they rely on to keep you quiet. Good luck.