Proxy...I don't own one but I have played the same model Wattage has for a couple of hours. They definitely have a distinctive tone...fat would be the word to describe it. It's very, very hard to get the 15 watter to sound anything but great.
If you check out http://www.guitarist.co.uk/gear/gear.asp you will find a couple of Orange reviews that are very informative. www.proguitar.de has some samples under the demo section as well.