I have had the chance to fly a viper powered Hawker, a 600. Compared to a 600 fan it had a little more gumption. And yes it is the noisiest aircraft this side of a F14.
Yes they burn fuel like its going out of style. But its not a major problem, as you have to stop to refill the oil anyway. The oil issue is because the viper was originally a drone engine. There is no scavenge pump on the rear bearing and the oil from that bearing is blown overboard. You also have to pump alcohol into the engine for anti-ice protection.
There are a few advantages to the viper. One is the overhaul times. Under part 91, if it makes power, its legal. And second, is the engines are so cheap right now, you don't overhaul, you just take the bad one off and put on a better one.
The biggest problem is cost of operating. Not just fuel, but also inspections, etc. Hawkers are inspection intensive. I happen to like Hawkers, they are a nice flying aircraft, but the British methods of manufacture and design seem to make for aircraft that require at least twice as many inspections as necessary and the disassembly of the aircraft to do them.
If you are looking at purchasing one, also keep in mind schooling. There are very few instructors at accepted schools that know anything earlier than a 700.