A few months ago, after the heartbreak that is the Quantaray 28mm, I was desperate for a fast, cheap manual wide angle lens. Although nothing worth owning will match the Quantaray's $25 price tag, I was surprised to find that even some film-era Nikon lenses can be had for a pretty good price. A few are even current production models! As far as fast, manual, wide-angle primes though, there are several sets of lenses to choose from. The most popular focal length in nikons manual lineup are 20, 24, 28, and 35mm. Right off the bat, the 28mm models are a no-go. They are rarely sharp across the frame, and the optics are overall sub-par. The 20mm ones are overpriced for the quality, so those are off the list as well. To me, 35mm is a little too tight to use as a wide angle lens, so my clear winner was the 24mm. Even the autofocus models of the 24mm 2.8 are reasonably priced, however they are poorly built. This leaves the 24mm ai-s, which, surprisingly, you can still purchase brand new, albeit at a higher price.
By most modern standards, the 24mm ai-s isn't exactly a great performer. It distorts, vignettes, and the sharpness leaves something to be desired, even compared to many modern zoom lenses. The upside, though, is that it can often be found for under $150, which is hard to beat as far as wide angle lenses go. In addition, its manual aperture and focus rings make it compatible with nearly every f-mount body ever made. And because of the large flange distance, it can be adapted to most camera systems with minimal loss in compatibility. So while there are better options, the 24mm 2.8 is definitely among the most economical in the wide angle range.
The build quality is like many others in the AI/AI-S series; which is to say that they could probably survive a small nuclear catastrophe. So, if/when prima Donald gets us into a nuclear war, at least you can have peace of mind knowing that your 24mm will be ok. Mine has taken a few falls(including one on concrete), and works just as well as the day i got it. The focus and aperture rings are among the best I've used. While it doesn't have quite as long a throw or as much resistance as something like the Rokinon lineup, the focus ring is smooth as butter, and very easy to fine tune your focus with. Because of the more sensitive ring, it is much easier to focus on moving subjects as well.
My favorite aspect, however, is the tiny size of the lens. though its aperture tops out at almost 2 stops less than most modern 24mm primes, the lens is less than half the size and weight of any other full frame lens I have used at this focal length. In fact its only slightly larger than my 50mm D series lens. At this size, i can afford to take it nearly anywhere, even without a camera bag. It fits nicely in exterior pockets on a backpack, the water bottle holder on my bike, or even my jacket pocket. The downside to this is because of the short length, the front element sticks out and is highly susceptible to scratching, or other damage. I would highly recommend a filter and lens hood if you don't mind the added size, because without them, even using the wrong lens cap can smudge or scratch the glass.
As far as the optics, they are good, but not great. Like I said before, you aren't exactly choosing this lens over the 24mm 1.4 for its image quality. But for the price, its definitely one of the better performers you can buy. Lightroom does a descent job of controlling the chromatic aberration, but the distortion and vignetting are a little trickier. Your best betis probably creating your own custom preset for these issues, but if needed, the profile for the D series autofocus version will work as well, although it does not completely eliminate the vignetting despite the two being almost identical optically. This lens isn't exactly soft, but its not pin sharp either, although I've found stopping down to help. In my experience, it is sharpest between f/4 and f/8, but it is surprisingly good from wide open down to f/11. Past f/11 the sharpness drops drastically, and at f/22 the results are borderline unusable.
All in all though, it's really not that bad, especially given the price. When shooting on film the grain tends to hide its optical flaws a bit, and when shooting digitally, Most of the issues are correctable. I highly recommend it if you can live with the flaws, and you'll be hard pressed to find a better wide angle lens at the price.