I've had the SD5 with vocalizer and pattern expansion since Nov 06.
Then became a dealer.
Compared to the T2, G70, I have found that it seems to give a more realism to live play.
There are less styles than the SD1, but they can be added with the pattern expansion, the addition of the 16 direct call buttons are great, this gives instant recall of registrations, GM access, and any function for a instant use.
My only complaint is that when you are playing a style, you can not search midi files. You have to stop the style play then go to midi files
I have the SD1+ and the SD5 set-up at my shop, for side by side comparison.=