I have one, its a tape version, bought before digital came into vogue. I've toyed with the idea of updating to digital.
Attorneys use these things all the time, to dictate papers, letters, memos, etc., for transcription.
I purchased mine fore precisely the purpose you outline, sans shower!
The issue is you have to have the damned thing with you at all times wherever you go, and I suppose that would include the shower. Ideas would come and I'd never have the thing with me; or, I'd be in bed and the thing would be on my desk in another room; or, vice versa. Then there's keeping track of tapes; what is on which tape, what did I do with
that tape. Of course, digital might solve some or all of that---particularly, if you can
mark and keep track of each recording. Keeping track is the thing.
If you have the discipline and/or necessity to go over the recording each day and make notes, then you have less of a problem; but, if you're like me and
store your ideas on the tape, and go over it when you have the time, locating past ideas can be a problem.
Just my experience.
Digital removes many if not all the tape issues, but the main crux remains----YOU'VE GOT TO HAVE IT WITH YOU AT EVERY MOMENT!
After awhile, I just gave up; though, I plan to try it again, digitally of course!
Luck!
P.S., in my experience there's also the issue of whether to simply dictate notes, or, to, if writing creatively, simply sit back and let go, and dictate a few pages. I always dictated notes---which sometimes were and most often not
inspiring----the moment was lost.
When I try again, I plan to let my mind spew into the thing! IF I can find it when I need it!