I'm writing this review primarily to provide a comparison with the similarly-priced Solis Maestro (I paid $140 for both). I benefited a lot from the reviews on this site (particularly on my purchase of a Macap M4 grinder for my espresso) and wanted to add my two-cents' worth for future shoppers. I used the Solis Maestro for a number of years, and was pretty happy with it, although I did have to have it repaired twice. I think the aesthetics of the Maestro are much nicer, but on most counts, I find the Infinity markedly superior in performance. I have the model with the brushed metal casing, which is much more substantial than the plastic Maestro body.
I have to offer the following disclosure: I changed (infrequently) from drip to espresso or French press grinds on the Maestro, but I have purchased the Infinity as a dedicated drip grinder (though I may occasionally grind for French press), in large part because of things I have read on this site. That said, the Infinity appears to be superior in allowing you to switch from one grind back to another and have the same results you previously had on that setting. The Maestro does an extremely poor job of this, and even when I left the grind setting alone for months, the grind would vary from day to day. The evenness of the grind (i.e., limited range in particle size) was pretty good on the Maestro, but is better on the Infinity. The Infinity also is definitely quieter than the Maestro.
Now here is where the Infinity totally kicks the Maestro's butt: much of the coffee I buy (such as from Peet's) is dark roasted to an oily sheen (yes, I know the arguments against this, but I know what my taste buds like). These beans simply would not feed automatically in the Maestro. I had to stand there with the hopper lid off (adding to the noise) and, using an appropriate implement (the plastic handle of an old, cheap coffee scoop), I would have to continually jam the beans down into the grinder while grinding. (It also required a degree of finesse: if I didn't cram hard enough, the beans wouldn't feed; if I crammed too hard, I ended up grinding some plastic, which is why I didn't use a metal implement!) If I stopped doing this, the beans would immediately stop feeding and the burrs would just whine while grinding air. I talked to Solis about this and they said it was just inherent in the grinder for certain types of beans. My work-around ensured that I got a cup of coffee, but it was pretty labor-intensive, and did not allow for any multi-tasking. By comparison, I have never once had to coax the Infinity. The beans feed automatically without fail, whether I am grinding medium-roast beans or dark, oily beans. That alone leads me to rate the Infinity considerably higher than the Maestro.
The Maestro does trump the Infinity on two counts. It has a pulse button on the front, allowing you to manually time your grind. I grind my coffee one cup at a time (unless I have company), and prefer to eyeball the dose, and this button made it easier than it is on the Infinity. Although you can nudge the Infinity timer dial from 0 toward 1 to achieve the same effect, I found the recessed button on the Maestro more convenient.
The second issue is with the grounds bin and chute design. I use a one-cup drip method (that is, when I'm not slurping delicious espresso) with unbleached paper filters. It was easy with the Maestro to pull out the grinds bin and hold the open paper filter under the spout, with every ground dropping into the filter. I could also stick a jam jar under there if I wanted to grind a larger amount and forego the static cling headache that comes with the plastic bins. Unfortunately, the former is quite difficult and the latter is impossible on the Infinity. The shorter grounds hopper leaves little room to fit the paper filter into the recessed area. The grounds chute is set back, making it even harder. By bending over so that I can look up and under to the chute, I can carefully position the paper filter to capture the grind as it emerges. However, the placement of the filter has to be just right or I get a little (or a lot) of the grounds falling down the sides, missing the filter. For my method, this feature of the Infinity is a pain. I am so accustomed to eyeballing my dose that I am reluctant to just use the bin that comes with the machine, and then I'd have to deal with the mess created by static electricity, in addition to having a much harder time eyeballing my dose.
Apart from these two complaints, I'm extremely happy with the Infinity. When I consider that it cost the same as the Maestro, I realize that the Maestro was really overpriced.