There are still some fairly low time G-IV's out there and they are dirt cheap right now. You could get a very nice airplane and put the new PlaneDeck cockpit in it and be very nicely equipped up front for many years as the ADS/B, FANS, etc. programs start. From a product support standpoint you can't beat Gulfstream and the range is nice, however, there's no getting around the fact that you will pay more to own a G-IV than a challenger....It's not exactly a Prius.