Well the only thing I'm worried about is the Polyphony.
128 sounds good, until you realise that (from what I've read) the wonderful voices this Yammie has are often the result of up to 6 (!) different sounds to make one of it's (admittedly great) "super sounds" if you will.
I am (relatively) young, but even when I do Top 40 gigs, I don't have the need to do 30 minutes of Trance (as Nick obviously does - more power to him though!) as we just do the Radio Edits of songs (sometimes remixes) and I often mix them (beat matching where I can) into the next song.
I'm tempted with this particular Yammie (I really am) I'm just not sure it could cope with our style, which is using SMFs with sampled loops and lots of live playing (sustain pedal and all).
IF your situation is different Nick, and you WON'T be doing many "traditional" gigs (make sure of that by the way the future could change for you) then I say :
Do it!
I'll be going down to my local to have a look at this board myself....