I've been shooting one since '85 or thereabouts. It is quite sharp and contrasty. It's good until you get into the corners when it softens; there is very minimal light falloff. I put a K2 filter behind the lens and a permanently mounted (read: glued) lens shade. The format is excellent especially compared to 6x6.
I've had several images made with this camera rejected from 'toy' camera competitions when the learned jury members said it could not be a toy camera which created the image.
Your mileage may vary.