Detroit Modular is my go-to place. I've never had issues ordering from them. I've had a couple of self-created issues, but they sorted me out and I was shipped the right gear. They ship same-day or next day, generally.
Perfect Circuit is very active on Youtube. However they are super-slow to ship. But sometimes they have fantastic sales for holidays.
Sweetwater is fine. But they don't stock a lot of modules.