I used Unity in a work environment for about a year and a half, so I feel like I have a reasonably informed, if potentially a little outdated opinion, since that experience was some years ago. Whilst Unity is generally more mature there definitely are areas where I strongly prefer Godot. (Disclaimer: I am a FOSS nerd)

First up the added Unity maturity isn't always as helpful as you'd expect. There were many areas that felt very incomplete, requiring us to write our own solutions, or find third party ones often at cost. An example was I believe we encountered strong limitations with the built-in AI Navigation system that made it pretty useless to us. There were third-party navigation solutions, but this sort of summarizes part of the problem with Unity: there is a lot of third party addons, but a lot of them felt like things that just overcome the often confusing limitations of the original product that I already paid money for. Lots of game engines can suffer from being particularly suited for certain genres and not others, even supposedly generic ones like Unity. So if you were making something that was kinda weird and would require a lot of bespoke special work, using Unity didn't really get you any wins.

Godot plays better with VCS systems using a nice human-readable scene format called tscn, that is swapped for a binary format on project export. I find this format is usually readable enough to review scene file changes in PRs, with the usual exception being a scene that was primarily imported geometry data. To get around that we'd import geometry data into bespoke geometry scenes, and they'd be nested by reference into the scenes that you'd like to be able to review diffs on. Additionally this scene format merges nicely in git, and has allowed me to work on team projects and have people edit scene files in their own branches without fear. Unity (and Unreal) at least at the time, had nothing approaching this. There was a Unity text-scene format, but it was a merge nightmare regularly. In practice we ended up using a VCS product (I believe perforce) that allows you to exclusively check out a scene file. Which at least stops people stepping on each others toes too much but hinders productivity.

Unity as of last I heard still does not have an out-of-the-box solution for nested prefabs, with many opting to use a commercial add-on to supplement the short-coming. This feels like it has been the single most complained about Unity pain point, so it was very confusing that nothing really seemed to be happening. Godot uses an approach that I find much more elegant. There's no distinction between a scene file and a prefab, which allows for some nice refactoring where something becomes a prefab after not initially being conceived as one. You simply have the ability to make a scene graph node that is a instanced reference to an external scene, and this nests nicely with no limit that I've ever encountered.

The Unity Editor was a bit of a dog. It regularly crashed and experienced general slowness. I find Godot much more stable snappy, and don't experience anywhere near the amount of tool frustration. But I have heard that it has been quite a bit more stable in the past year or so.

I encountered a lot more weird rigid design in Unity. IIRC if you wanted to runtime load content such as textures or models, they had to be inside of one specific subdirectory of the project. In general Unity seemed to force its philosophy of project organization onto you, while Godot will happily go along with whatever approach you want.

I still think there are reasons to use Unity. It is more mature, companies generally want access to an existing talent pool, and let's not forget that often it is worth sticking to the tool you know. But I definitely have found that I enjoy working in Godot more than I did Unity, and as a fairly experienced programmer I don't mind not having as big of a community to rely on for assistance. I don't work as a game programmer anymore, but I continue to do hobby projects near exclusively in Godot.