I've actively searched for years to find a system to dump my brain into and Notion is the absolutely perfect fit for me. The fact that everything is a page, anything can go into a page, and you can nest forever on the fly is exactly what I need to model my actual IRL problems.

Putting together a Christmas list? Create a list and start adding stuff. Ahh crap, I know I want a new TV but I don't know any specifics. So I just open up the TV item in the list and dive into my research. Create a database inside there for prospective options, a separate view for finalists. Copy in images, links to articles and reviews without "losing my place."

I don't have to spend any mental energy thinking about how to organize my notes because I can just pick a direction and go without being stopped by anything. Everything lives where it's most relevant I guess it how I'd say it.

imho The primary value is their pared-down databases that mostly just work like you want them to.

They offer the ability to export to markdown, so I don't think using it would lock you out of reverting to that option

Beware that for us any export has been broken for months with no real answer from Notion support other than: we know.