I switched from Keep to Obsidian as well. It depends on your goals. For me, I was saving things in Keep that I wanted to have forever and I don't trust Google to operate the service forever. The exported data is also not super portable. And there are things I want to save that I don't want on a cloud service. So I switched to Obsidian which gives me a simple and portable file format, privacy, and I trust myself to keep those files safe more than I trust Google.
For me, plaintext (like Markdown) is a strength over proprietary or binary formats and I've accepted the tradeoffs. It's the primary "good reason" I use Markdown. I have confidence that text will always be readable in the future even if I don't have the app that made it. Secondarily I find most word processors overkill with toolbars everywhere and I do not like using them.
Same experience... There's a lot to like about notion and I chose it over everything else and am using it professionally and personally. But the sluggishness is really starting to bother me