First separate two jobs the category blurs: crosslisting (publishing one catalog to many channels) and sync (keeping quantities true afterward). Many crosslisting tools do the first and quietly poll the second. Judge any platform on three documented facts: sync cadence with a number, what gets metered (orders, listings, GMV), and whether it attaches to existing listings by SKU without relisting.
We publish ours: under 3 seconds, orders and listings never metered, SKU-attach. The category-wide comparison with receipts: the roundup.