I had own both 35mm and a 50mm focal length. I sold the 35mm recently and got myself a 24mm lens. But no matter which lens I owned and sold, I still have the focal lengths that are important to me in my camera bag. The real question I believe anyone should ask is, which focal length (especially prime lens) you should own if it is the only lens you will buy.
As for myself, the type of shoots required will generally determine the gear selection, but the answer is there is no supreme prime lens to rule them all. As a prime lens user, I like to work with a pairing of primes. I have used the 35mm / 85mm combo, but over the years I am now gravitating towards 24mm / 50mm combo. It works well for events photography that doesn’t require any telephoto lens.
So which is which? Well, I used to like 35mm as I like to shoot environmental portraits. It is also the best walkaround travel focal-length, in my opinion. I gravitate to taking a photo of people with a little bit of breathing space in the composition, to show the environment and surrounding. But somehow, 35mm is not wide enough, and I want something wider. That’s where the 24mm lens comes into play.
It is best paired, with another lens that can isolate your subject better, and 50mm is such a perfect lens to pair the 24mm with. Where the latter will be the wide-angle lens, the 50mm will be the one where you want your subject to stand out better. A 50mm lens is a little bit tricky to compose, but once you get the hang of it, it is much better than a 35mm. You need to take a few steps back, and voila, you get the same view of a 35mm lens but with more compression and bokeh. The key to remember is, you can get the same view of a 35mm lens with the 50mm, provided you CAN take a few steps back. See, it is all about the working spaces that you have that will generally determine your preferred working lens, not which lens suits your vision more.
I believe, framing and composing with a 35mm lens is easy to understand. Still, personally, I prefer 50mm focal length all the way. And since I am focusing more on portraiture now, I will favour 50mm any day. In a nutshell, 85mm for tighter portraits, and 50mm for everything else.
All lens mentioned is in the 35mm full-frame equivalent.