My items are standardized enough to feature an SKU, however, often customers want slight changes, a specific shipping date (won't be in town for a month), and we operate with a fixed lead time of several weeks.
Think high value, very low volume, and somewhat opinionated customers.
Etsy seems to handle everything well because it manages the lead time, customer notes, SKUs of items, etc. The fees suck and that's why I push my website–but the system works decently for my needs so we do everything to keep it running smoothly.
However, we sell on WooCommerce, Amazon Handmade, and Etsy–so we're stuck constantly updating a spreadsheet.
I tried SellBright but there's no ability to manage customer notes.
Shippo at least provides a consolidated list and works very well for printing labels–but that's all it does.
We've recently changed from USPS to UPS and I see there's a "UPS Marketplace shipping" section. I am almost tempted to see what UPS came up with but suspect it sucks and won't even surpass Shippo for what it can do.
Speaking of shipping–UPS account managers aren't good for much or am I mistaken?