I have one. The amp doesn't have a preamp out, it's a simulated mic out which means it already has a cab simulator of sorts built into it. And frankly it's not that great sounding. And unfortunately you can't bypass it. The stock speaker was OK but not great. A couple months ago I bought a marshall 1960 BV cab and to me the amp sounds fantastic through that. I work two jobs so it's hard for me to find the time but finally the other day I got a few minutes to sit and try to get a decent recording with the thing. This is a completely sloppy and generic guitar riff that I made up on the spot to a click, then added in steven slate drums afterwards just to get a quick feel of how it might sound in a mix.
This is my 08 gibson les paul with stock pickups into an ibanez tube screamer, boss ns2 then into amp. The amp is on the lead channel with the gain and volume both around 2. The tube screamer had the drive at zero, and the tone and level both up around 9. I have an mxr eq in the loop but it wasn't on for this. It's recorded with a single sm57 off axis going straight into my echo gina soundcard. The only thing I did after recording was add a high and low pass on EQ. Oh and Izotope ozone is on the master track. There are two guitar tracks panned hard to each side.
Anyway, sloppy playing/mixing/etc. aside I think it's a pretty decent sound with lots of potential. It's really damn close to the sound I was trying to achieve. I can't wait to sit and record an entire proper project with it. But this little clip should give you an idea of what the amp is capable of. I enjoy playing through it, the sound standing in front of the cab is truly fantastic as far as I'm concerned.
http://dl.dropbox.com/u/16441720/6505 test.mp3