[3/6/20 UPDATE] After some more time with these tuners I've decided to knock off one star. I still really like them, but only on a couple of my guitars.
I'm a big fan of the Snark tuners. They do a great job, are easy to read, and well...they're good. At first I thought these micro tuners were going to take over the top spot. My problem appears to be finding the perfect sweet spot that allows them to register or register accurately. Once you find that spot you're golden, but I'm still struggling to find it on a few guitars. I don't believe it's necessarily dependent on the type of head as I've gotten them to work at least briefly on all of them. For instance, on one strat it was a piece of cake. On another with the same style of head, I can't seem to find the sweet spot. My Snark stays on that one. One an Epiphone ES-339 Pro I found a good spot, but on a Epiphone Les Paul I can't count on it yet. That said, here are some highlights:
Pros: - As accurate as any similar product when I find the right mounting place. - They are VERY discrete. - I love that I can EASILY flip the orientation of both the screen AND the text on the screen to suit my needs. - The discrete nature and secure ratcheting clamp lead me to forget they are even there. In fact, I started with a two-pack and I'm about to buy another two-pack. I just leave them on my guitars.
Cons: - I am not always easily able to find the sweet spot, as mentioned above.
Other: - I'll be interested to see how long they hold up, being plastic and relying on a ratcheting system. They definitely don't feel cheap, but if you sat on one or dropped it I can see it breaking. That said, again, I just put them on the guitar and forget about them until I need them. Once they're installed it's highly unlikely you will damage them. Just give the ratchet a little last squeeze to make sure it's on tight and you're good to go.
If anything [else] changes I will try to remember to update this. Hope that helps!