The AMI standard marimba sets, as you will see on the AMI website, come in 2 different tunings – C major and Eb Xhosa tuning.   C MAJOR: The former, being the well-tempered concert pitch that we all know and love, is best suited to applications where the marimbas will be played alongside other instruments – many schools prefer this tuning, which allows arrangements involving a conventional orchestra, for example.  E FLAT MAJOR: The Eb tuning has been developed to cater for the natural scales used by traditional music and especially to accompany singers.  The tuning is not quite well tempered, but definitely gives richer chords and is the tuning of choice for traditional choirs and cultural groups. Marimbas tuned to E Flat cannot play with Marimbas tuned to C Major. So the tuning used by other groups in your area may affect your choice, because you may want to get together with other local bands for workshops or competitions.