I can say only VST's are good thing. Also if you use LIVESTYLER it is great.
What ever you will use you can fast change between style and you can play what ever you want.
Exchange is possible. setup need to be done in same way.
You can have severaly keyboards (VSTs) on one system. Here you are limited only with RAM, CPU) HD are so big that is not a problme there anymore only possible problem is piping between SATA HD and motherboard.
So guys I'm for VSTs on arranger.
Enjoy whatever you play.