Each supplier platform trades off differently between price, shipping speed, and ease of integration:

• AliExpress — largest selection, lowest prices, but typically the slowest shipping (often 2–4 weeks) unless you pay for faster logistics options.
• CJ Dropshipping — offers warehousing in multiple countries, which can cut shipping time significantly versus direct-from-China AliExpress orders.
• Zendrop / Spocket — curated supplier networks with faster US/EU-based shipping options, at a higher per-unit cost — often worth it once you’re past pure validation and shipping speed starts affecting your reviews and return rate.

All of these integrate directly with Shopify (and WooCommerce via plugins), auto-forwarding orders and tracking numbers — you rarely need to manually place each order once set up.