Great coffee, but it takes a little work and patience
Positive Product Points
The Cona is attractive (It looks like it belongs in a chemistry lab), makes a very clean cup, is easy to clean, and makes an outstanding cup of coffee.
Negative Product Points
The glass, particualrly the upper bowl, is fragile. Making coffee requires a 2 step heating process because the alcohol burner will not heat the water to boiling in anything resembling a reasonable time (if ever).
Making coffee in a Cona is a conversation item. Most people have never seen one and thus find the process interesting the first time.
As I stated in the negatives above, in order to make coffee you must first boil the water on the stove in another vessel, add it to the Cona and bring it back to boiling with the spirit lamp. It is a bit of a pain, but the coffee produced is outstanding, it is very similar to the coffee from a press, but cleaner. The Cona also gives you complete control of the brewing time. I leave the lamp under the pot for 5 min after the water has all entered the upper bowl; I also stir the grounds with a stirring rod (chopstick) after the upper bowl is filled.
I've only had the Cona for about a month now, thus far I have had no problems with stuck brewing. I use about 2.5 oz of the same grind that I use in my drip machine with very good results. It takes a good 15 to 20 min to get a pot (after you boil the water on the stove) so don't be in a rush.
In order to clean the lower bowl you will need a bottle/glass brush. The opening is small and no other cleaning method is practical.
This is not the way to make coffee at 5AM while you are still bleary-eyed and needing a caffeine fix. On the other hand, I think it is ideal for after dinner or mid-day pot, when you can appreciate an outstanding cup and have time to make a pot.
In another review someone commented on heating in the Cona on the stove...this is a bad idea. If you have ever taken chemistry and boiled water in a glass beaker you probably used the boiling rocks to get the vapor bubbles to release in something resembling a controlled manner. The same applies in the Cona. (drop a fragment of a bean in the pot and watch it as the spirit lamp heats the pot...as it approaches boiling the fragment will be the source lots of the bubbles.)
Pure water, in glass does not have any places to enhance the formation vapor bubbles (the bubbles you see in boiling water) thus there is no localized boiling and the whole volume will rise to the boiling point before bubbles are released. The rapid addition of heat from the stove, combined with inserting the funnel could/will result in a sudden flash of steam, add to this that you have plugged the hole in the top is a great way to get a scalding geyser in your kitchen.
Sweetmarias, Point, click, it shows up in a few days.