I bought this just before Christmas so it's been in constant use for the last 3 1/2 months. I've been through many different coffee makers over the years and for my particular tastes this is the best. No, it won't make you an espresso but if the thing you are after is the best 'long' coffee you can get then I think this device takes some beating. It gives the depth of flavour of a French press except without the sludgey bits - very clean and zingy. It's marginally slower to use than a French press but much quicker than a filter machine and I think the results are far superior.
When I use it, I actually boil the kettle and put boiling water straight into the bottom jug. I then put the coffee-loaded upper funnel into the bottom jug and turn the gas on.
The water immediately rises into the top jug and starts bubbling. I (carefully, it's top heavy!!) give the brewing coffee a stir then I turn the heat down as low as it'll go and give it exactly 3 minutes. At that point, it's off with the heat and remove the jug to a heatproof trivet. A minute or so later, you're good to remove the top funnel and drink.
From the point the kettle boils, it takes you less than 5 mins to have perfect coffee. Using this method, it's repeatable, sludge-free and (for my taste) perfectly brewed. I found the timings a little erratic if I just stuck it on the gas with cold water and of course this method takes longer / uses more energy - the kettle is more efficient :)
It's very simple to clean but of course as it's a whole load of glass the clumsy need not apply! Not a cheap item to drop....
In all, I love it - it was around £45 when I bought it and it seems to have now gone up unfortunately..... Still worth it if you like coffee IMO.