Well, I've had the opportunity over the past couple of weeks to get to know my Classic 300, so can now report on my impressions. Firstly, the bells and whistles are all really cool - when you switch the amp on, the display says "warming tubes" and a bar moves across the LCD screen while this is happening, a bit like a progress bar when you are installing software on a computer. After that, the screen shows "biasing" for a little bit longer and then the amp switches to standby ready to rock. That process takes around 60 seconds all up. There is a 3 way switch on back panel that gets you into two diagnostic modes where the LCD screen displays individual bias readings for each power tube in real time, as well as plate voltages (I think) for each tube in the preamp/EQ section.
Once taken off standby the amp is whisper quiet, and the fan is barely audible in a quiet room.
There is quite a large range of preamp gain available, but it's only in the upper reaches of gain that the signal gets overdriven easily - somewhere from around 1 o'clock onwards. The overdrive is not SVT grit style or creamy at all, it's more of a heavy and thick harmonic overdrive - it certainly cuts through in a big way. In the rehearsal studio playing assorted classic rock covers I was keen to see how loud this head could get (teamed with the sealed Markbass CL104 quaddie) - with the gain at noon and the master at noon the volume was unbearably loud, even with earplugs, so I can confirm that the Classic 300 has headroom to burn. This one is running Sovtek power tubes with quite a few hours on them according to the previous owner, so when it comes time to replace the tubes I'll probably try some JJs or Mullards.
One of the front panel controls switches the biasing from "long life" to "hifi" - ie. the tubes will run hotter in hifi mode. The hifi mode is slightly brighter, with a tad more gain, but in a live gig situation with a rock band, the long life mode sounds good enough to me. The hifi mode would probably be useful if recording or in a "less rock" gig situation.
Things I don't like - hard to read the controls in bad lighting ... but this will improve as I become more familiar with the control layout. The shape of the head is a little unusual - it is higher and deeper than most tube heads, so it's looks "different".
Otherwise, at the price I paid for this used (USD$800) it is a keeper. I can't say that I would ever pay the original list price for a new one though, that price is over the top.