Well, as far as I know myself, I should care about this, I'm a hell of a curious person about these stuff.
I've always written posts including the word 'wow' after many firmware updates. So I decided to wait and let some time pass after the Q1 release. So I can 'wow' now!
After I got my new blue beauty (the Schecter with active Duncans), and both knowing that the 5153 Red Channel is G3'ed/Q'ed and having Cab Pack 7, I don't give a poop anymore. I'm sure that it is both the guitar and the firmware (I've done some brief tests).
Finally, after two years, I played for two hours without touching a damn knob. This was not the case even with my beloved mini rectifier's real knobs
This firmware made me hear/feel the most dramatical change for me (I started from fw10 or 11, I don't remember which one).
Two months ago, I actually considered to buy a DSL5c and get rid of all the details about the digital domain. But those details are reduced to only a high/low cut at the cab block from low cuts from low/high cuts whereever I could do it. Since this also would be the case with micing a real amp, I don't really care about getting the real thing or the modelling generations or other stuff anymore, I just play.
This may seem stupid, but after the quantum firmware, I don't even need to use 2% or 3% of room reverb anymore! This is good, since I always needed but hated reverb on my guitars. It was a love/hate relationship. 10%-20% CPU is the bonus!
Now it is time to choose the 5-10 best alloys of Mikko's all awesome cab packs (decided that they are the best for me finally), stay away from Mesa/Boogie sims (they are different beasts, not bad certainly, but when you get used to them, you just cannot get used to any other amp, so I choose to have more options), and play till the morning!