[trumaestro]

You're asking a notoriously difficult question to answer. I'm pretty sure consensus remains that mechanical keyboards are superior in pretty much every way to membrane keyboards, but the actual feel is something you just have to experience for yourself. If you know anyone with a mechanical keyboard definitely ask if you can do a typing test or play some FFR to try it out. Other consensus is that no one ever really goes back to a membrane keyboard by choice, so it's a good investment especially if you use your computer a lot for other tasks too.

Be warned that mechanical keyboards can quickly become an expensive customization rabbit hole. Virtually every single piece can be bought a la carte. Just starting out, you'd be much better served with virtually any whole pre-built keyboard you can buy.

Switch types are pretty self-explanatory. Linear switches are probably the most like membrane keyboards, with no real feedback in a key press until you hit the bottom, feels basically the same all the way down. Tactile switches have a more noticeable bump you can feel part way down a key press closer to where it actually sends the key signal. Clicky switches make a click on each key press and can be very loud.

For rhythm games it becomes much more about feel. I've owned 2 mechanical keyboards, one with Cherry mx Brown switches (tactile) and one with Cherry mx Red switches(linear). Between the two I would personally recommend linears. The Brown switches are heavier but I felt I had more control, but with the Red ones I have much more speed. Your results may vary.

tl;dr get a pre-built mechanical keyboard with cherry mx red switches or similar, it's well worth it