Well, I sort of learned (as one does) in about 1986 or so, on an Atari of some sort or an IBM clone or just one of those computers that used to be around back then. Not my own.
I've naturally been going on that and probably typed countless lines in Usenet, IRC, web, notes, code, configs and whatever files. But it always bugged me that it's just kind of ballistic hammering with any and all fingers that happen to be near the next key.
So, I went and got a very minimal split keyboard to see if I can learn something new. The setup and layers and all that has not really been dull, but I've been pecking away slowly at typing.com and trying to keep my hands on the home row like it's 1989. I thought that might balance it out.
I just got the first unit certificate at 25 wpm. And, hey, I managed to type this post. Maybe I'll get better with time.
One problem with using a nonstandard layout is that it makes you depend on using a keyboard that you control.
I don't use Dvorak or another non-QWERTY layout, but I do swap Caps Lock and Left Control. I'd say that that's a preferable layout in general, since I think that virtually all users use Control more than Caps Lock, but if you're a serious emacs user, you really need the traditional Unix-style layout, because you use Control heavily.
But it also means that if I'm on another system that I haven't configured, I'm prone to making mistakes, and I'm slower.