@kc2ihx Everyone has an opinion, of course. Mine is I strongly recommend starting with a straight key so you build in the brain/muscle rhythm of the code. Then move to other keying devices if you wish. I went from straight key, to electronic paddles, then to a bug, now I prefer sideswiper.
I like making the code with my hands and I like the ability to radically change speeds on the fly if I want. You can only do the latter with straight key and sideswiper.
Long sessions, especially at 20-24 WPM gets tiring with a straight key. But a sideswiper is effortless, as easy as electronic only you're forming all of the code with your hands.
That's my experience, anyway. But I consider straight key a fundamental skill and I still use it if I'm working a beginner who wants to go real slow. I have three kinds of keys in parallel here so I can switch on the fly.