For multi-product updates on Shopify Plus, GraphQL bulk mutations beat REST by ~10x. AAosync went from minutes to seconds.
Math
2,000 product updates via REST: 50+ seconds at 40 req/s, plus 429s. Same via GraphQL bulk (15/call): ~133 calls = ~4 seconds. Rate limit stops being the bottleneck.
Use REST when
Single-product, no GraphQL equivalent, webhook-fire reliability matters.
Use GraphQL when
Anything bulk. Multi-store sync. Anything where rate limit is the bottleneck.