It's true conda used to be slow, but that was mostly at a time when pip had no real dependency resolver at all. Since I started using mamba, I haven't noticed meaningful speed problems. I confess I'm always a bit puzzled at how much people seem to care about speed for things like install. Like, yes, 10 minutes is a problem, but these days mamba often takes like 15 seconds or so. Okay, that could be faster, but installing isn't something I do super often so I don't see it as a huge problem.
The near instant install speed is just such a productivity boost. It's not the time you save, it's how it enables you to stay in flow.
In my previous job we had a massive internal library hosted on Azure that took like 5 minutes to install with pip or conda. Those on my team not using uv either resorted to using a single global environment for everything, which they dreaded experiment with, or made a new environment once in the project's history and avoided installing new dependencies like the plague. Uv took less than 30 seconds to install the packages, so it freed up a way better workflow of having disposable envs that I could just nuke and start over if they went bad.
