Torque is related to current but holding torque is of little relevance for CNC use. More critical is winding inductance, the smaller the better and winding resistance, again the smaller the better. These determine the real torque available and how fast it drops off with speed. On that basis the smaller cnc4you motors are far far better. The ones on Aliexpress look like an older design and may represent over stock of something built for a specific customer.