The Canon 50mm 1.8 one of my first lenses I ever purchased and one of the most recommended lenses for very good reasons. It’s a great portrait lens on a crop body and a great all around lens on a full frame body. I don’t have a full frame digital body, but I do have a film EOS body which I picked up cheaply a few years ago.
What’s great about it
Price, cheapest canon lens you can pick up for around a $100.
Very shallow depth of field you can achieve shooting wide open at 1.8. Also useful for shooting in low light situations.
Small and light, easy to throw in your camera bag. Make sure you have a good aim. Or have a floor made out of rubber. Or have the common sense to place an expensive and fragile piece of photography equipment in your bag rather than go going full out and knuckle-balling (baseball term for my non-American-continent readers) your precious thrifty-fifty into the nearest wall.
What’s not so great
Many people complain about the build quality. It is made of plastic, but I wonder what people do with lenses that that really matters. I have dropped my nifty fifty various times and it has always kept on ticking. The last time I dropped it, the front element glass popped out and I was holding two pieces of a former one-piece lens.
Immediately I turn to Google and find many other people who have done this. Everybody talks about how easy it was putting it back together even when some of the plastic inner pieces are broken. I like to think of myself of at least being equal to the average net-user and it takes me 15 minutes to put the lens back together which now functions perfectly.
The focus ring is hard to maneuver when handling it manually. This is especially the case when shooting video. But I can’t think of other lenses that handle this well, so it may be not a real piece of criticism.
When shooting wide open it is hard to keep the focus accurately. Focus-Recompose doesn’t always work well when dealing with such a narrow depth of field. But again this is more related to technique rather than characteristics of the lens itself.