Magento vs McKesson Connect vs Cardinal Direct vs Shopify Plus for medical supplies?

Honest cut, medical-specific:

• McKesson Connect / Cardinal Direct are vendor portals, not e-commerce platforms. Great if you want to resell their SKUs without holding inventory, terrible if you want your own brand identity, your own SEO, or to drop-ship from a second distributor. You don’t own the customer.
• Shopify Plus handles a clean B2C Medicare direct-ship catalog under ~5,000 SKUs reasonably well. Falls apart on three medical-specific things: HCPCS-as-attribute indexing, prior-auth checkout flow (you’d need a $20k+ custom app), and EDI 850/855/856 to McKesson (Shopify EDI apps exist but are fragile).
• Magento + Hyvä handles 20,000+ SKUs cleanly, has native EDI integration paths via TrueCommerce / SPS Commerce, supports HCPCS as a first-class product attribute, can pause checkout for prior auth via order-state machine, and lets you ship B2B hospital procurement + B2C Medicare direct-ship from the same store with separate catalogs.

Most DME merchants above $2M GMV land on Magento. Below $1M, Shopify Plus + a few apps is fine. Above $10M, especially with multi-distributor EDI + GPO contracts, Magento (or Adobe Commerce + B2B Companies) is the only real answer.