I've bought this lens used for nearly 80€, so I was not expecting the perfection. The very light and compact plastic body confirms the price impression. Nevertheless I've hoped to use it stopped down 2 steps, at f/4, on my full frame Canon 5D. At this aperture the image quality is very good except a single corner (upper left) where some blurring occur.
I've used also in the day, and I find this lens a pleasure to use. The image quality is easily visible to be by far better respect to zoom lenses, such as my Sigma 18-200 f/3.5-5.6. At the same F.L. and aperture, the 50 mm has pinpoint details. Higly advised.
For little better performance you may consider the Canon 50 mm f/1.4.
The images below better show the behaviour. And here are some shots made with this lens: Milky Way Panorama, Cygnys, Southern Milky Way, Scorpius,