It is a tight race between the Tognana cups and the Illy cups, each coming in tops or second in most categories, but in the end, art and style wins over functionality for me (as long as the art and style is also functional).
The Saeco cups were an even third, with a special nod to how they handled differently from all the other cups and the line marker inside, but also a pan for the excessive price and the saucer which has a different shade of white (and, I suspect, different porcelain) from the cups.
The Francis! Francis! cups. Those poor cups. Aesthetically, they score high, and the packaging is first rate and seriously impressive. Too impressive in fact. The FF!! cups are prime examples of style winning over functionality. Too much money for too little a cup.
Tognana... on one hand, I want to give the overall nod to Tognana. The cups are built rock solid, have what is almost the ultimate in "classic" shape and lines for an espresso cup, and heck, they bounce off tile floors! (don't try this at home - I'm not responsible if yours break when mine didn't).
But overall, I give the nod to Illy. Illy wins big time in design, looks, and artistry, and is also the nearly perfect espresso cup in terms of functionality and attention to details. All it needed was maybe a bit more thickness, and it would win without any serious consideration for any of the other cups. There's so little to complain about with regards to them - maybe having the marker inside the cup showing 1.5 ounces instead of 2? Yikes, that is a micro detail.
What more could you ask for in the Illy cups? A cheaper price, of course. But beggars can't be choosers. Illy wins for me as the near perfect espresso cup, and I highly recommend them to anyone who considers espresso and artform, one that should be framed by an equally impressive artform.
And if the price knocks you out, you can always get the logo cups for much cheaper.