Having made the switch to Linux right around the time Windows was rolling out the copilot update (actually I wanted to switch away after the October 2025 update wouldn't install on my computer and I later learned this was actually the good outcome with that update), I can't say much about copilot.

So I asked your question to Perplexity and what I can glean is copilot only seems to work with select Microsoft apps for the time being, is proprietary and people report it's kinda broken and stubborn, though I expect they will fix that soon.

The open-source aspect is mostly important because crush can connect to different LLMs, such as Deepseek's which is very cheap (and why I recommend everyone do Crush with Deepseek, we are talking something like 10-50x cheaper than other APIs).

Crush can also act over your entire system and do web stuff, including scraping content. It can run terminal commands such as git clone to download a git repo and run the program it offers, or write a python script just from you prompting it (for example I made a script that downloads the entirety of ProleWiki as .txt files by just telling it to make that).

Copilot can apparently do some of that scripting, at least to an extent, but you're still locked with the LLM they want you to use, whereas with crush you can even add your own LLMs, even local ones (though they're really not great at doing this type of work so stay on deepseek - but if deepseek ever goes down or there's a better model that comes up, you can easily switch to it with crush)

Personally I would say if you haven't used copilot yet, try to disable it entirely (it's bound to be a resource hog always running in the background) and get on crush haha. On windows installation takes 5 minutes by just running a command in the terminal.