If you haven't already, read the detailed review of the Solis Maestro by Mark Prince on this website. After owning one for four months, I thought I'd make a few other observations...
First, this is a great grinder--my espresso has improved tremendously since buying it. Everybody who says that the grinder is more important than the machine (within limits, of course) is right. Although there are better and more expensive choices than this one for straight espresso, my significant other has a small kitchen (and drinks drip coffee), and it was the right price/performance/size/ease of use choice for us.
There seems to be very little coffee in the chute after grinding because the path from the burrs to the coffee container is nearly vertical. This is a very good thing!
My old Braun KMM20 was deafening. This is very quiet by comparison; as far as I'm concerned, the $129 was worth the reduction in noise alone.
It's fairly durable; a stone made its way into my coffee yesterday, and the burrs aren't significantly damaged. The top burr is easily replaceable. The bottom burr would be harder to replace...
I have a few quibbles with it. The following "problems" are extremely minor; please remember that as you read them.
Grinding into a Portafilter:
I find that it's too much hassle to do so. The ground coffee container at the front of the machine has to be removed to grind into a portafilter. Because I use more coffee when making espresso than will loosely fit in the filter basket, some coffee grounds make it around the portafilter as I grind, and these grounds make it difficult to re-seat the coffee container without cleaning them out of the base of the grinder (which takes a few seconds with a brush). This is what I meant when I said above that some parts fit too well; if the grounds container didn't fit so well, those few stray grounds wouldn't matter.
Once, I held the portafilter up against the chute so that the grounds didn't go around it. Big mistake--this caused the grounds to clog the chute, and I spent the next fifteen or twenty minutes cleaning them out. Don't repeat my mistake--leave a gap between your filter and the chute while grinding. The grinder isn't prone to clogging--it hasn't before or since.
I find that the machine doesn't quite grind finely enough for Turkish coffee--so save your burrs and don't use this grinder for that purpose (I say "save your burrs" because it sounds like they touch when the grind setting is fine).
To be fair, I didn't buy this grinder expecting that it would be used for Turkish coffee, and I wouldn't expect any other grinder of this type to do it either.
I would like it to grind a bit more coarsely for French press or gold-filter drip coffee. It's not bad, though, and the mud I get may be due to a little coffee left over from a previous espresso grind; hard to say.
To make it easier to repeat a previous setting after making large adjustments to the grind, try turning the control past where you want it, then returning to the desired adjustment.
If you're having trouble setting the grinder to a finer grind, there are probably bean fragments in the burrs that are physically preventing you from moving them closer together. Run the grinder momentarily; this should make the adjustment easier.
After many, many pounds of coffee, my grinder was difficult to adjust even after running the switch for a moment. I removed the hopper, removed the top burr, then used a brush to clean the coffee bits from the white plastic gap surrounding the bottom burr. It turned freely again after that.