The Tranquillo is over-rated and performs poorly on most of what you want a grinder for.
Positive Product Points
Reliable Consistent Grind Good size hopper, enough for a pound of beans
Negative Product Points
Poor user interface. Inconsistent grind quantity Lots of places for coffee to get stuck and need cleaning
Although I've been making espresso for a couple of years, I'm sure that I'm pretty inexpert (I still use my original Starbuck's Barista, with a Solis replacement for the pressurized portafilter), so take my grinder observations for what they're worth. However, I bought the Tranquillo based on CoffeeGeek reviews - probably influenced by Len Sabo's front page advice - and am inspired to write this cautionary review in response to fact that Len's 2006 review is still featured on the front page. So:
The most obvious issue right off is the techie approach it provides to setting the time of the grind. You stick a little screw driver into a hole on the side of the machine and turn a plastic headed screw (dunno how long that'll stand up). The assumption seems to be that you would do this once and then seldom adjust it. But, of course, you change it frequently when beans, humidity, etc. change.
The limits of the time setting are insufficient as well. I have it turned all the way to the long side to get the coffee load I want.
Even more serious is the inconsistency of the load. The amount of coffee the Tranquillo grinds for a charge seems to change with the amount of coffee in the hopper. (It changes well before you are almost out.) What is a grinder doing for you if it isn't giving you a consistent charge?
Then the mechanism for setting the fineness of the grind is very crude. It's a slotted ring on top of the machine. There are no marks to allow you to change it for different purposes and get back to other settings you use. I marked it with whiteout, but that's pretty unsatisfactory. And if you take the ring off to clean the machine (the grinder area collects a lot of coffee), it will fit back on in any old way, so your markings are no longer accurate.
And there are real limits on how fine a grind you can get. My 30 second shot with one coffee becomes an 18 second shot with another brand, but I can't set the grinder any finer without apparently damaging the grinding heads.
Finally, the funnel that catches the ground coffee and drops it down into the portafilter is a mess. It sprays the coffee and collects so much coffee each time you grind that you must bang it to make the full charge fall down into the portafilter. And then clean it. It's about the worst concept I could imagine for redirecting the coffee from the grinder into the portafilter.
So, why give it even a 5 rating? I don't know. It is a low end grinder and I've been getting along for a couple of years, so that's gotta count for something. But I wouldn't buy it again.