In my experience with IPSec VPN, Satellite is fair at best, about 1-2x dialup speeds and that was with Wildblue. Hughes may be a small improvement due to a little better latency.
If your able to get 3G, it is a good improvement for VPN as opposed to Satellite.
You could try to get a compatible mobile broadband router to share the USB connection over several computers. I'm using an Cradlepoint MBR1000 with 3G usb card and I wouldn't consider going back to Satellite as its much better if you can handle 5GB caps.
I have VPN / non-VPN stats in my review of AT&T 3G, »
Review of Cingular Wireless by lastmile4