Context: Lens released in 1990. I don't own this lens but have used it. I used to own the slightly larger EF 50mm f1.4 USM.
Often the practicality of a lens is more important than the image quality because if a lens is practical and functional, you are more likely to use it. This is a review of the Canon version of the "nifty fifty," the EF 50mm f1.8 II - this lens has since been replaced by the EF 50mm f1.8 STM. Based on my experience with the 40mm STM lens, I suspect the newer 50mm STM produces sharper images and has slightly quieter autofocus.
The EF 50mm f1.8 II is practical due to: as cheap as a kit zoom lens but with way better image quality, and a much better maximum aperture. The downsides: the f1.8 II has a cheap looking exterior with a small manual focus ring right on the front, so it wasn't the most enjoyable lens to manually focus; it is not sharp from f 1.8 to f 2.8; it is not weather sealed; and, it does not have image stabilization (IS). I consider a fully functional lens to have weather sealing, autofocus (AF), and IS: this lens has one out of the three. If you don't shoot in the rain or show, or at the base of waterfalls, then weather sealing is probably not relevant to you - but the other two requirements are relevant to most people. This lens is really small and light, which makes it easy to carry around in the camera bag, and easy to take on vacations, etc. The downside to the small size is the tiny manual focus ring and NO DISTANCE INFORMATION WINDOW. What? That's right, no window. People who only use autofocus probably never look at the window anyway. As far as value for money, this lens cannot be beat! (Except maybe by the newer EF 50mm f1.8 STM.) This lens is so cheap that if you were using one and broke it, it's no big loss as it's easy to replace.
Filter: should you use a filter on this lens, considering the how cheap the lens is? Some people don't because the cost of a filter is equal to a significant chunk of the cost of the lens. I still would put a filter on it, just so that I could easily wipe condensation off the front when shooting in humid conditions.
Image quality is great once stopped down to f3.2. At f1.8 it's very soft. Corner softness and vignetting at there at most apertures.
This is a great lens for the price and either this or the newer EF 50mm f1.8 STM is recommended as a first lens for most people with a Canon DSLR. There are people who shoot this lens for many years, and I know someone who has shot ONLY this lens for some years now and has got excellent results. In the hands of a master, this is a great lens. The point is, great results can come from this lens, particularly with casual portraiture and shots of the kids over the years. In fact, it could be argued that 50mm is the perfect focal length for shots of toddlers and young kids since they are always moving quickly and hard to keep in the shot with an 85mm lens when working in the small working distances of a house - especially the older houses that are not open-planned.
If only they would build IS into these f1.8 lenses, and truly silent AF, then they could be really amazing for video... but if they had IS, it would definitely increase the price. On that note, Tamron has a 45mm lens with image stabilization and it is more expensive.