Both of those choices are terrific in the ballroom catagories, but the X1 has a great advantage with multiple outputs, mic input (WITH harmonizer)and a hard drive option.
The VA7 has a 100mb zip disk that stores LOTS of midi files, but no real mic input.....just the variphrase input, and it's too sensitive to use as a "live" vocal mic.
I just got the new XD9, and I think it has the best sound I ever heard as far as the ryhthm section goes - the solo sounds are tremendous too, but lots of the others are as well.