The Cona produces a great cup of coffee. The coffee is only in contact with glass so there's nothing to absorb any of the coffee flavor and no "off" flavors to pick up. Similar to press pot coffee but without the "mud". Elegant appearance as well.
Negative Product Points
The cost seems a bit high.
The glass is relatively thin and seems fragile, but no problems so far :-)
When filled with hot water the brewing time seems about the same as for drip coffee. I don't find the Cona any more difficult to use and clean than a drip brewer or french press - and I prefer the cup from the Cona. This has become my default method of brewing when I'm not drinking espresso.
I really like the looks of the Cona and vacuum brewing appeals to my technical roots.