I have a Fender Mustang III V2. It doesn't have quite as many features as the new Mustang GT line but it's arguably better sounding. This could partly be due to it having a single Celestion 12" amp speaker as opposed to the more full-range hifi speaker used in the GT-100 (from what I've read).
The Twin Reverb '65 preset is probably the one I use the most. Not sure exactly how close it is to a "real" amp but sounds pretty nice to my ears none the less. I'd certainly be tempted to pick up the Twin Reverb Tone Master if I saw one for a good price. At the moment I'm pretty content though and I do use some of the added features over a normal amp like built in pedals, noise gate, and usb sound device (to allow direct recording on a computer). It even sounds quite nice in it's own right with the modelling turned off.