Sorry, Dick, I didn't answer your original question...!!

I lean more towards the guitar for accompaniment, which has probably more to do with the fact that it was the first one I found I could cope with, rather than anything else.

The guitar's continuing popularity, despite its obvious shortcomings, is probably for that very reason - it is far easier to play a simple accompaniment in any key (helped, maybe, by a capo).

When teaching people to play, I show them how to hold down a D chord, strum and sing 'Old Macdonald Had A Farm'... takes less than ten minutes, and they feel they have moved a mountain!

I choose D simply because the A7 chord is so easy to move to and from, and plenty of songs will work with just those two chords. Then I break the bad news, and show them G...!! By this time, though, they are hooked enough for it not to matter, and they will work on it.

This method was developed during many years of teaching primary school children - they found E - A - B7 too taxing, C - G - F (chords in order of being taught) only worked if you used four-string versions, which wasn't ideal, but most of them coped well with D - A7 - G... those who didn't weren't sufficiently interested.

I did find that E - A - B7 needed to be taught in one go, showing them which finger didn't move in each change... never lift a finger unless you have to! E to A - leave the index finger on 3rd string, 1st fret, A to B7 leave 3rd finger on 2nd string, 2nd fret, and E to B7 leave 2nd finger on 5th string, 2nd fret. Rather than a song, I use a 12 bar blues to practice the chord changes, but a good song is 'The Happy Wanderer' (valdi-ri, etc!).