I have the G7X (mark I) and decided to buy the mark II.
Here's what I don't read/hear often about the G7X mark II (compared to the mark I):
Soft shutter. Compared to the mark I, the mark II has a quite significantly softer shutter button. Focusing only needs the tiniest bit of pressure without any clicking sensation, while taking a shot still has a clicking sensation (though still softer).
Softer control ring clicks. Aside from having the option between a clicked or clickless control ring, even the clicked ring is still softer compared to the mark I. It's a click click click and no longer a clack clack clack, if that makes sense.
More recessed buttons. I'm not sure I like it. I find it harder to click the buttons now, and I definitely like the way they are in the mark I. They're also softer (which I do like).
Thicker body. It's still not huge by any means, but the thicker body was still surprising to me. It's also heavier.
Better grip. Not only does it have a grip, the grip is made of soft rubber with good traction. I can see this being the first part of the camera to show wear and tear, though, it's rubber after all. The shape of the grip doesn't really help with the way I grip my camera, I feel it's too far to the side. I prefer the OG EOS M's grip, which is a bit to the center.
ND filter now automatic. The mark I has a built-in ND filter, but we have to turn it on manually. The mark II has that option, too, but it also has an Auto option: the ND filter kicks in when the scene is too bright for the chosen settings. That said, I prefer to turn this off and opt for a safety shift instead (the camera changes the settings automatically, e.g. closing the aperture, if it's too bright). The reason? I don't know if the ND filter decreases the image quality. Pretentious, but there it is.
Full-fledged picture styles. Gone are the color profiles (or whatever silly name Canon was naming their profiles back in the mark I). We now have actual pictures styles, with the ability to finetune the threshold and amount of sharpening (which I've never seen before in a Canon camera) aside from the usual contrast, saturation, and color shift. We can now shoot RAW in B&W. (Which we couldn't in the mark I, RAWs are always shot in color.)
Could've sworn the contrast is better in this camera (I use the Neutral picture style, customised), while I find it hard to get a good contrast in the mark I. (Too low and there's not enough contrast in the midtones, too high and I'm losing too much dynamic range.)
Camera freezes while dumping buffer. This is the biggest letdown for me so far. I don't know how it goes in the Sony land (or Panasonic), but in other cameras I own (mostly DSLRs) the camera is still usable while saving the shots to the card. By "freezing" I mean you can't even zoom the lens! You can, however, take more shots. Clicking the 'Play' button meanwhile means your camera just freezes while it's struggling to display the shots, and you can't do anything, even shooting. If you don't shoot RAW in high-burst this shouldn't be an issue, though. The camera is generally snappy and fast.
There's an AE-L button on screen. I don't know whether I missed this on my old mark I but I could've sworn it didn't have an AE-L button on screen. (They both don't have physical AE-L button, though.)
The mode dial is harder to turn. I totally understand why they did this (my mark I changed modes in my bag far too often), but I must admit this is disappointing. I can't turn the mode dial while composing the shot, for example. It's just too hard and I can no longer flick it with my thumb. The ex.comp dial changes directions, which is annoying after a year of using my G7X. I must admit it was confusing at first, but now it's gotten intuitive, and I have to re-learn the dial on the mark II. No big deal though, just a matter of habit. I suspect the ex.comp dial is now harder to turn, too, but it doesn't present a problem for me (still easy to turn) so meh.
Remote shooting is noisier, with the camera beeping in every autofocus and emitting a loud shutter sound in every capture (so you have a beep-schrack every time you take a picture). I don't know why Canon insists on this (aside from regional regulations, maybe).
Harder to change AF type. On my mark I the "Ring Func" button was assigned to switch between face-detection and single-point AF, and I could switch between them with just a press of the button. Now on the mark II we need to press the button first, which only brings up a dialog to choose between face-detect and single-point. I can't say this is a smart decision. Do you need a "Are you sure?" dialog box, too, Canon? Maybe get me to fill a Captcha too just in case I pressed the button accidentally?
Could've sworn the Eco mode now turns off the camera faster which might explain the increased CIPA-based battery life. Haven't A/B tested with the mark I though so I'm not 100% on this. Changing the camera's orientation still wakes the camera up, though, which I don't understand.
VERDICT: a worthy upgrade if you're looking for a speed upgrade when shooting RAW. If you don't shoot RAW (and don't want to), I don't see much reason to upgrade from the mark I to the mark II.
4 stars, for what it is, it does the job pretty well.
