Although you wouldn't guess it from the model number, the Brother HL-6180DW is best understood as a heavier-duty version of the Editors' Choice Brother HL-5450DN that I recently reviewed.
Duplexer and 550-sheet capacity standard, 1,050-sheet maximum; Low running cost; Ethernet; Wi-Fi
Although acceptably fast for the price; it's slower than you might expect for the rated engine speed