Square

Square provides a unified commerce ecosystem, famous for its simple card reader and POS software. It seamlessly blends in-person, online, and mobile payments. Target audience is small to medium retail and service businesses. It uses transparent, flat-rate pricing (2.6% + $0.10 for tap/dip/swipe).

It ranks highly for its cohesive ecosystem encompassing hardware, software (Square for Restaurants, Appointments), payroll, banking (Square Banking), and lending. Its ease of setup and all-in-one dashboard makes it incredibly popular for brick-and-mortar-first businesses going online.