I read music and enjoy playing pieces in keys other than C, but it is my preferred key, nevertheless.

Sometimes I'll be reading a tune that's written in, let's say, D, but it doesn't quite hit the sweet spot for my sax sound, or perhaps a trumpet or acoustic guitar.

That's when I'll use the transposer to move up or down till it sounds right to me.

I don't have any trouble hearing one key and playing in another...guitar players use capos with no issues, so I really can't see why it should be any different for keyboard players.

I suppose those with perfect pitch, might have an issue...I don't have perfect pitch, but I do have a pretty good sense of relative pitch...I can hear chords, and identify them quite easily.

I love having the transposer...I could play without it, but it's too handy not to use.

Ian