Just curious, Donny, and others that do this, but what percentage of your act is mp3's?
Presumably, they aren't actual recordings of a live band (REAL karaoke), but are recordings of arrangers or WS's playing SMF's, yes?
So what happens when a sizable proportion of your show is these recordings, and you move to a totally new, presumably MUCH better arranger...? All your mp3 backing is still at least one, and possibly two or even three generations old. You spend a fortune on the arranger, only to sound, at least in the rhythm section, EXACTLY the same as you did several years ago (and it's the rhythm sections that have improved the most in the last few years).
Every time I change arrangers, I have to re-do my entire repertoire... For me, at least, there's no point in spending a fortune on the latest greatest, to sound mostly the same as I did before. So I stick to SMF's, and tweak them for the new sounds and drumkits. Maybe this is why I hate to change arrangers as much as some others...