HL-5070DN and MFC-L5850DW share specifications such as Automatic Duplex Printing (Yes), USB (Yes), Ethernet (Yes), Product Brand (Brother).
The main differences: Printer Functions (HL-5070DN: Print, MFC-L5850DW: Print, Scan, Copy, Fax); Print Technology (HL-5070DN: Laser/LED, MFC-L5850DW: Laser); Black Print Speed A4 (HL-5070DN: 18 ppm, MFC-L5850DW: 42 ppm); Print Resolution (HL-5070DN: 2400 x 600 dpi, MFC-L5850DW: 1200 x 1200 dpi).
HL-5070DN may suit users who need its differing values, while MFC-L5850DW benefits those who need its paired strengths. Review the specs table above before deciding.