For synthetics, I'd say Wintec. The newer ones have the nice Cair panels and Adjustable Tree.
For leather, in the $400 range, I'd go with something used that was Made in England, France, Germany...basically anywhere in Europe. You won't be able to get a new European saddle for $400, and I like used leather saddles because you don't have to break them in! Good brands could be Crosby, Stubben, Nelson Pessoa, Childeric, Hermes, etc.