If you already have a decent laptop then rather than go with these you would be better off getting a universal VST such as Kontakt 5 or Halion Sonic as you get a much better quality of sound along with greater flexibility, the only down side is that you have to set up the VST yourself to get it to work with your keyboard, but at least you will be getting a great experience in the process.
Bill, you do have a point. I have lots of VSTs besides Kontakt. In fact, with vArranger combined with HQ soundfonts and VSTs for solo voices I have been trying to go all software. The are definitively lots of pros and some cons. Then I ended up getting a Ketron SD40. Always excuses and self-justification for my GAS!
The V3 module I am getting has some unique sounds that you can't easily find in software. Or if you do find, they can be very expensive. I thought that the small module with MIDI in and USB host would make a good module. V3 Sound does have high quality sounds. In fact, one or more of their sound cards made their way into VST versions! I have both the hardware and software version.
Btw, does Holion Sonic still require a USB dongle? That's a deal breaker for me. The only exception for me is vArranger.