I would not agree with that either, the Legacy can be made to sound pretty good at Low volumes with some careful tweaking and by using an effects pedal with an input level control in the loop.
Admittedly you wont get the best out of it unless you crank it but even at low volume it sounds at least as good as any Line 6 amp ive tried.... & I've tried a few!
EG Vetta, Flextone Spider 3......
What digital modelling amps have going for them is versatility and combined effects and no tube amps can compete with that....but it depends really on what you want.
I have run the gammet of wasting hours twiddling with Line 6 tones etc etc but have now come back to the less is more way of thinking.
In my opinion no amount of processing can better the simple sound of a good tube amp with a tad of reverb in the right hands!
but then that's just me!! Many people love the versatility and variety that Line 6 gear has to offer and all power to them!