HL-1260 and ECOSYS M2635dw share specifications such as Automatic Duplex Printing (Yes), Maximum Paper Size (Legal), Maximum Custom Media Width (216 mm), Minimum Custom Media Length (148 mm).
The main differences: Printer Functions (HL-1260: Print, ECOSYS M2635dw: Print, copy, color scan, fax); Print Technology (HL-1260: Laser, ECOSYS M2635dw: Kyocera ECOSYS laser); Black Print Speed A4 (HL-1260: 12 ppm, ECOSYS M2635dw: 37 ppm); Print Resolution (HL-1260: 600 x 600 dpi, ECOSYS M2635dw: 600 x 600; up to Fine 1200 dpi).
HL-1260 may suit users who need its differing values, while ECOSYS M2635dw benefits those who need its paired strengths. Review the specs table above before deciding.