First off, this is a pure espresso grinder. If you're looking for something more flexible, go elsewhere.
See the Coffeegeek Detailed Review for all the salient points. I have one proviso: the grinder motor and resin burr carriers are beefier than those on the Solis grinders, although not at the commercial grade of the flat burr set. Given the good Solis track record, I doubt that the higher quality Innova set will present a reliability problem for a home user. The brushed aluminum case now being offered makes for an attractive package, and the grinder matches well with stainless steel espresso machines.
INITIAL DIAL IN
The extremely fine stepless adjustment makes this a challenge. Here's a trick that'll get you to the right ballpark in about three shots: Remove the cover off the top of the grinder, and note the factory set position (don't try it, it's way too course). Start turning the grind wheel finer, operating the grinder without beans until the burrs start touching (you'll hear high pitched noises when it happens). This is about a 1/5 to 1/4 turn of the burr set, but about 30 to 40 turns on the adjuster screw (I said extremely fine!). Make a note of this zero point. Now set the grinder halfway between the factory and the zero and grind the first test shot. Depending on how it goes, go to the new halfway point finer or courser. Keep doing this halving trick. You'll be in the ball park by the third shot, and at near perfect timing by the fifth.
The design calls for the owner to hold the portafilter under the spout, activating a pushbutton, and grind till its full. This might be a good idea if the grinder worked quickly, and the grounds flowed like a liquid. But on the Innova, this concept is living in a fantasy world. It takes about 30 to 40 seconds to grind a double, the grounds come out staticy and spill. Finally, about 4-5 grams are retained in the grind chamber, these have to be flushed out with a stick or by tilting and thumping the grinder. This is not just a huge hassle, it also detracts from the quality of the espresso shot, since the portafilter is cooling off while one goes through these gyrations.
There's a work around: The grinder has an on/off switch. I've jammed the actuator button in with a toothpick end, and use the on/off switch to grind into an espresso cup that up-ends neatly into the filter basket. I've even gotten somewhat proficient at thumping the remaining grounds out into the cup without spilling a lot over the counter; an alternative is to use a slightly curved spoon handle or stick to loosen up the grinds clogged in the grind chamber. I dose by leaving the bean hopper empty, and putting the correct amount of beans in for each dose. Fortunately, this grinder works very well with so few beans in the hopper.
The grinder is noisy; less than a hairdryer or vacuum cleaner, but enough to drown out a conversation.
In an ideal world, single dose grinders would have a locking connection for the pf, similar to a grouphead's, and an adjustable pushbutton timer for dosing. Finally, such a grinder would completely clear the chute and grind chamber of grounds. That way the operator wouldn't have to stand there like some yokel, pushing a button and thumping the grinder. I can dream, can't I? Actually, nobody would put up with an espresso machine which had to be thumped, or which sprayed grounds all over the place at each use; why not expect the same standard from grinders? None of the things I mentioned is rocket science: a push button timer costs a few dollars at Radio Shack, so does a lock mount for a PF, so do anti-static charge rods or bristles, and so do sound insulators.
Here's where the Innova conical makes the grade big time;the grind is in the same league as that of any commercial grinder. The test results Mark gives in the detailed review are mirrored by my own experience. The grind is extremely even, and this permits a finer grind, since there's no dust to choke the espresso machine, and since it creates a more even extraction. In addition, the stepless adjustment makes it easy to achieve perfect shot timing.
All this show up in the cup. Espresso from it has better crema, and the origin flavors are simultaneously less astringent and more distinct than in shots from my old Mulino, or even from the NS Grinta and Isomac Granmacchina that I had a chance to try out.
If you have a home espresso machine with a commercial group, this is the least expensive grinder that will give you an optimum grind. Also, since home machines require time to warm up and recycle between shots; it's slow performance won't create extra delays. But I cannot recommend this model for people who want to make several espressos in a row on a semi-commercial or commercial machine; it's too slow and labor intensive to keep up.