I don't own a vintage electric mistress, but I do own Mooer's elec-lady, which is known to be really close sounding to it.
I directly compared this pedal to Mooer's e-lady and I could not hear a difference, honestly.. However take this with a grain of salt, I'm not a big pedal expert.
I do suspect this pedal uses the same components, so for 20€ you can't really go wrong... Try it. Mooer's E-lady is 3 times the price.