Robot Attack is the winning design of the first Design by Humans' contest, and the result of a collaboration between 25 artists. The winners, members of Black Rock Collective, will receive a $5000 kickoff money prize. The t-shirt is on sale for $19.
I find the design awesome, I truly do, but to answer my own question, no, I don't think it makes a great t-shirt, not one I'm interested in having at least.
Threadless was the subject of the Times column Consumed, Mass Appeal, which discusses the workings of the Threadless tee-ocracy and its appeal:
"The casual viewer of Threadless.com cannot help being struck by the surprising degree of consistency — maybe even similarity — in the designs. “It’s a barometer of what’s going on in art and design right now,” Kalmikoff suggests. He likens it to a school of fish moving in a particular direction until a new leader suddenly emerges, everything shifts in that direction and somehow the crowd arrives at something close to an aesthetic."