ANY amp sounds better at higher volume. It doesn't matter if it's solid-state or tube. Note that this volume does not mean that the amp has to be on full blast, just louder than what many think of as "bedroom volume". I'd say "loud TV volume" and beyond or something. It's got to do with how we hear things and pushing the speakers a little.
I've never been quite happy with modeling amps. I loved the sounds I got from the Yamaha DG combo I had, but not the fact that it sorta made all guitars sound similar. Nice, pleasing sound, but if I plug in a Strat, or a 335 or a LP I want them to sound distinctly different. I find this is a problem to varying degrees on most modelers and solid-state amps and they don't react to picking softer and harder in as nice a way as a good tube amp does. So tube amps it is.
Over the years I've tried nearly all the "tube taming" solutions available. Really low watt amps, attenuators, dummy load w/lineout into separate poweramp, Power Scaling...out of those Power Scaling worked best in terms of retaining the tone of the amp without compressing or changing the tone (excluding how we hear things differently at different volumes). The Einstein's master volume in my experience works just as well. I use my 50W Einstein combo at home (in an apartment no less) and it does the sounds I want. Does it sound better at a higher volume? Yes it does, but only because of the increased volume rather than the tone changing that much. It's not like say, old Marshalls that sound weedy and thin at low volume and roar like beasts when cranked.
The master volume is a bit touchy on the lowest settings and requires a careful hand to work but it's not like in some amps where moving the volume control 0.01 notches is a difference between silence and WAY LOUD. Overall it seems to have a pretty even range on the knob. The channel volumes can be used to fine tune the volume levels anyway so it's not a problem. The voicing switches on the first channel can also be used to alter the FEEL of the amp. Mode 3 is the most compressed so if you want a bit easier feel then just turn that on and turn down the gain for compressed non-metal/high gain tones.
Currently my only real beef with the amp is the 2nd channel. It's a great sound but the gain levels are stupid. Yes, I mean stupid. I find anything above 11 o'clock practically useless because there's so much gain. I intend to drop a lower gain tube into the V2 slot and see if that helps tame it. I think it'd be great if it could also be used as a rhythm/lead sound since the voicing is great but the sound cuts out if you turn the gain on 0. Gain on 0.1 is still a pretty high gain sound in my book. Peter really should drop a gain stage or add some sort of high/low gain switch there.
. Obviously the amp sounds better and really comes alive when you crank it a bit, but don't be fooled into thinking it sounds bad at lower levels. Still, I advise you to crank it as often as possible, because that's what tube amps are all about. Enjoy dude.