The shape - that's what got everybody talking in 2012. What kept them talking was that this was an all-tube amp with a built-in speaker, an external speaker output, a line-level output, and an 1/8" stereo input.
Play back a song while you're learning it? Sure. Get actual tube distortion instead of a simulation? No problem. Easy tube swapping without needing to re-bias? You-betcha. Change a tube without going broke? This is your amp. Love the tone, but need more volume? Plug the line-out into any amp you want.
I love this amp so much I bought a second one. The first recommendation I make to everyone: leave the back off. There aren't any exposed components that you could accidentally touch, and the tone improves immediately. The second recommendation: swap out the two tubes (12AX7, 12AT7) right away - the ones it comes with are placeholders, save them as last-ditch spares.