I hate that I can't use my laptop for notes in most of my STEM classes- not because the professors disallow it, but because there's simply no equation editor that I can use quickly and efficiently enough to take notes with. I tried latex, but it just requires a few too many formatting keystrokes and isn't WSYISYG enough to do on the fly (at least for me).
I'd be pretty happy with a digitizer, I think, but I wouldn't be able to stand all of the other little quirks of the surface.
For typing equations quickly, I found that a quick (not so pretty) ascii-art notation was fastest. I would transcribe them to latex later.
I only did that for a year or two before I decided that laptops and note-taking in general were counterproductive and switched to never taking notes at all. I still occasionally took notes on my own time while reading the course material, but I found that paying closer attention instead of trying to write things down ultimately worked better.
I found Word's equation editor (2007 onwards, not the crippled MathType before) very good for real-time typing of math in class. It's quite close to LaTeX when it comes to symbols, smart enough to use / for fractions or convert ยฒ to a superscript 2, etc. and generally requires far fewer braces because spaces or operators are used to separate tokens, e.g. a^15+4 yields ๐ยนโตโ+โ4 because it makes more sense than ๐ยนโ5โ+โ4 (what LaTeX would make of it). It also features WYSIWYG build-up of the equation as you type.
windows has an app that's surprisingly not publicized a lot called math input panel which allows you to input equations quite easily in other programs like word or onenote.
I'd be pretty happy with a digitizer, I think, but I wouldn't be able to stand all of the other little quirks of the surface.