I like Starline brass, have purchased 357mag and 44mag from them.
If buying in quantity of 500 or more, the discount price at Midway, plus shipping, is about the same as buying direct from Starline (at least when I checked). The nice thing about buying from Midway is if you just need a smaller quantity, Midway will break them down into smaller lots, like 100 or 250. If you already have an order coming from Midway, the shipping isn't bad.
I looked at buying once-fired 357mag brass before, and it surprises me how many places charge as much for once-fired brass as Starline costs new. No brainer.