I'm an event, military, and wildlife photographer that is required me to be ready for whatever is unfolding in front of me and be quick enough to draw my camera and capture the frame.
With this said I'm using Spider Camera Holster which is phenomenal in how reliable and convenient it is to use.
BUT and this is Big BUT.
My sister now using a Promediagear holster and oh boy what a difference it is! Something you should try in order to appreciate the way it works and operates from a professional photographer stemp point.
Important note: To be completely transparent I personally do not own a Promediagera holster as I'm too invested in other brands like Peak Design and Spider but believe me, with all my experience this is potentially the best option on the market for the foreseeable future!
For hiking around I used to use a strap which was fine for flat ground. But for steep up or downhills or climbing over rocks or trees, the camera would flop all over the place. With this holster, the camera moves around a bit but is anchored so that there is not a lot of flopping about. And super easy to grab the camera and bring it to my eye super quickly. The only negative thing is that it squeaks as I walk due to some rubbing of the pin shaft against the holster. But that might be fixable if I move the pin to a different orientation but will need some experimentation.