HL-5270DN and DCP-L5500DN share specifications such as Print Resolution (1200 x 1200 dpi), Automatic Duplex Printing (Yes), USB (Yes), Ethernet (Yes).
The main differences: Printer Functions (HL-5270DN: Print, DCP-L5500DN: Print, Scan, Copy); Print Technology (HL-5270DN: Laser/LED, DCP-L5500DN: Laser); Black Print Speed A4 (HL-5270DN: 28 ppm, DCP-L5500DN: 42 ppm).
HL-5270DN may suit users who need its differing values, while DCP-L5500DN benefits those who need its paired strengths. Review the specs table above before deciding.