Hmm. This is my fear with this amp - not having heard it of course - versatility as against true excellence, "3 very good amps" instead of 1 excellent amp??? I wonder.
Nah, imagine it more like this: You've got a really super solid state amp with a huge soundstage and crystal-like transparency. Depending on your DAC and the music, what comes in is what's going to come out...for the most part, because it certainly has a "house sound" which is difficult to put your finger on. I suppose it's more like how I described my iDSD micro when I first got it: it just screams analog. It's more like playing an LP as opposed to digital bits.
Now, you flip the switch to tubes. It's the same house sound. There's no difference in feel and quality, but now you have this lush creamy sound, yet without sounding bloated. Simply stated, the difference is smoother, more full and recessed. It's not hyperbole. It's akin to listening to a recording that you know sounds thin, but all of a sudden it doesn't.
I'll make this short, but Tube+ is a combo (simply stated) of SS and Tubes. Now we're really kicking into gear! This is a whole other amp, that has the speed of SS, yet the lushness of tubes. It has the same overall feel, though. You never feel like you're skimping on quality.
I'm short, the more different types of music you listen to, the more you'll get out of this amp. If you're like me you'll find that certain recordings of various vintages sound better depending on your settings. What this means is that you now have more flexibility than any other amp in the planet.