You can buy the illy's or you can buy the real deal, this is the REAL CUP...
Positive Product Points
One of the heaviest cups in the business. Triple-fired porcelain with a beautiful finish that can withstand abuse. The "Nero" black version of these cups are simply gorgeous. They're available in many sizes.
Negative Product Points
Finish quality varies from batch to batch, some have small defects but this is normal for a workhorse Cafe cup. They're a little pricey$ but you get what you pay for.
These cups come in so many sizes that I had to have them all. They're availabe in 2.75oz, 3oz, 5oz, 6oz and 10oz for the Nero (Black) series. I own just about every type of cup out there, including the way overpriced illy collections and I can say that the ACF's make the illy's seem so over priced. First of all, don't get me wrong but I love a beautiful illy cup with the great quality cut and finish of high caliber porcelain but not very appealing for everyday use. The ACF's on the other hand, beg for use and abuse and anything else you can throw at them.
They come sealed from Italy with a cardboard sandwhiched between the cups and saucers in a thick plastic heat wrap. It actually surprises me every time I get a set on how in the world they survive the big trip accross the pond and then make it through UPS or FedEx without busting everything inside. The law of physics gets challenged again when you pick one of these monstrosities up, they are HEAVY and powerful looking especially with the brown hot juice inside.
Storing them is the only problem I have since I have about 60 of them in the various sizes, finding a shelf strong enough to support these things can be a concern if you're limited with space and cabinet strength, sometimes I wonder how many more cups can I stack in there before the cabinet comes crashing down onto my beloved espresso machines. Another minor issue is that I don't have X-Ray Vision to watch the wonderful creme developing while the shot pours into the cup, I bought the Pavina Cups just for that reason alone. Washing these cups are a breeze compared to the Pavina's though, these aren't the little light slippery mouth-blown glass that others are talking about (and yes, "mouthblown" folks, let's get it right, mouths blow the glass not the hands, therefore, stop calling then handblown!).
In real world usage I think they speak for themselves, with this kind of weight and density they do one thing best and that's heat retention. Size does matter, epsecially with espresso cups and since these are offered in several sizes one can narrow it down to which their favorite will be. My personal favorite of the week is the 5 oz cappuccino size, last week it was the 6oz and the week before that it was the 3 oz....I think you get the idea of where this is going. If you love double ristrettos, look no further than the 2.75 oz Nero, while the pavina double-wall looks great, this cup has mass volume that makes a ristretto feel like an Americano in weight.
I bought most of the sets from Sebastian Little at www.greatinfusions.com. He's great to work with and he's kind of local for me (S.F. Bay Area) - he's in Santa Cruz. Anyways, his deliveries are always speedy and well packed and his prices are very good. I highly recommend his service and would only order from someone else if he didn't have a particular item in stock.