I am not sure about Horsley Quality and they are basic as barn door but prices are more than mamiya deal.
Holga uses medium format film but it does not make it better than Horizon.
And white horizons , never used , in box comes for 170 dollars and its glass and optical tecnology cant be find at many cameras. White ones are better because their finish looks thick , black ones are matte and dont give the user to trust it to an impact , so if you dont trust a camera , you dont take picture with it.