Donny,
I have no experience with BIAB or software synths but I do own and have gigged with vArranger. I use it with a Ketron SD2 module. Later versions of vArranger include built-in sounds and make the SD2 module unnecessary. One drawback to vArranger is the need for a very high end PC Laptop. A big plus for vArranger is it does indeed play styles from Ketron, Yamaha, Roland, and Korg. Another plus is the high level support provided by Dan the creator of vArranger. I use vArranger with a Roland A-800 Pro midi keyboard and have it programmed so that I never have to even touch the computer once the program is running - pretty neat.

FYI, by the time you get setup with vArranger. a proper PC laptop, and a midi controller you will have $1000.00 plus or more pending the price of your laptop.

I don't use vArranger much now because I am deep into my Ketron keyboards.

Deane