I don't know who needs to hear this but Gilette Venus Smooth and Gilette Mach 3 blades and handles are interchangeable
Mach 3 blades are anywhere between 50c and €1 cheaper per blade than even most basic Venus blades and they are WAY sharper and give a smoother shave with a little extra care.
Venus handles are WAY more comfortable to hold, especially when wet.
Do with this information what you will.