I can tell right away that I am going to love this mouse.
The texture of the thumb cutout is grippy--an important distinction between the 2S and the slippery-when-dry Anker Vertical. The center of mass is under the palm arch, and the weight is ideal, unlike the cloud-like Anker. I have large hands, and gripping this mouse felt natural right off the bat. With a 3/4" gel wrist rest, I feel a balance of weight distribution between the wrist and palm and reduced shoulder strain. The Anker's left button position causes you to move the cursor when clicking, a problem which the flatter design of the 2S avoids.
This is a replacement for my M510. I think the steeper angle, higher rise, deeper thumb cutout, and larger arch will help my wrist discomfort. I couldn't justify the expense of the flagship ergo/vertical mice, and the budget-friendly Anker Vertical is too flawed to be a good value.
The wheel modes are just inspired! You can select between glide or bumpy with an assignable button, and it optionally switches from bumpy to glide automatically when you scroll fast. I work with lots of PDF's and TIFF's where I either have 1000 pages to skim or need to zoom to 1000% and pan. Tracking is just as excellent as my other Logitech mice, whereas the Anker Vertical was jumpy and twitchy. I can't wait to try this on a game. Configuration and mapping options are pretty deep and Flow works between my computers nicely. I didn't know I needed these functions.
You give up tilt wheel panning... Enter the thumb wheel. This assignable control is superior to tilt wheel and is positioned perfectly. The sliver-like assignable forward and back buttons win the steepest learning curve award, but now after a day's use are already a reflex, right at the thumb joint.
I do wish it ran on AA batteries, or better yet an 18650 since I vape. There will be the additional hassle of charging it 6 times a year. I had a spare USB port seal (I highly recommend this cheap preventative) in the junk drawer that will keep debris from collecting in the port. Qi and USB C would be nice, but pretty soon you're talking about real money. Packaging was basic but adequate. A quality 4ft USB cable is included (no charger).
Overall I am impressed, and I feel like it was worth the little extra dough to get a quality tool with extra functions instead of a cheap toy of flimsy plastic. The ergonomic design is a big improvement over my old flat and small M510, and the flaws of cheaper competitor devices make them a poor value comparatively. It looks cool and feels great to use.