As quoted by an information sheet from school:
full sized keys
a selection of voices (eg violin, trumpet)
a selection of styles (eg march, waltz)
automatic accompaniment facility ( a must!), may be called 'chord'. 'ACMP' etc
detachable stand
touch sensitive
It also says 'MIDI keyboards and those equipped with disk drives are particularly useful'
THEN it says 'You may have to take your keyboard to school for lessons'.
I SO SO wish he'd stuck with his original choice, the trumpet! Back in my day you had an upright piano at home and went up the road to Mrs Smith's once a week. Don't think SHE came equipped with a 'disk drive'. And I have to say as, right now my 2 x DSs have our old keyboard out (a Casio?- which is as long as DS1 is tall!) they aren't at all interested in MAKING music but merely use it like a CD player, stabbing at the ready programmed songs...
Anybody have any experience?