Flagship seems like a reasonable choice of merchant services provider for high-volume businesses. It offers custom, month-to-month pricing, a bunch of hardware choices, and nifty, business-boosting features loyalty and gift card program creation. Still, Flagship seems to have a lot of online complaints. Do note that every processor gets complaints online, though. Closely consider your needs and review the fine print before working with Flagship — but remember, you can always cancel your month-to-month contract if need be.