Operator context
Longer answer
The right framing for tool selection at $5M+ is "what toolchain" rather than "what single tool." Migrations at this brand size routinely use four or more tools across the engagement: an automated migration platform for the seed load, Matrixify for custom-field reconciliation, Rewind for backups during cutover weeks, and Easy Redirects for the post-launch SEO discipline. iPaaS adds a fifth tool for dual-write cutovers.
For the automated migration platform specifically (the most-asked piece of the question), Cart2Cart, LitExtension, and Next-Cart are functionally comparable. They all support the major source platforms (Magento, WooCommerce, BigCommerce, Adobe Commerce as supported source) and produce similar output quality. The decision criteria are engagement model (self-service vs vendor-managed), agency network familiarity, and support responsiveness during cutover weekend.
Beyond the seed load, Matrixify is the workflow tool used dozens of times across the engagement — custom-field reconciliation, mass edits, B2B price-list import, post-launch catalog cleanup. Brands that under-budget Matrixify usage during migration consistently pay 20-30% more in agency reconciliation hours than brands that budget it generously.
For specific source platforms, the toolchain has source-specific additions. WooCommerce migrations almost always add WP All Export for ACF/Meta Box field extraction. Salesforce Commerce Cloud migrations replace the automated platforms with iPaaS (MuleSoft, Boomi) because the wizards do not handle SCC complexity cleanly. Check the source-platform shortlist for the specific toolchain.