I've been using the TZ110 (the TZ100 model sold in Singapore) for close to a year. Frankly, most of the 1 inch sensor cameras are pretty similar in image quality. Previously I had the RX100 III. I also have a few other cameras including a SLR so I'm pretty familiar with advanced shooting.
The TZ100 is a game changer and there is nothing like it that reaches 250mm. Although the EVF is a little small, it works well and at least it has one! It focuses fast and has 4k video. It also has a 4k photo mode for action shots where you can isolate a frame in perfect sharpness from a 4k video stream. I'm sure the Powershot G7X is a good camera, but as I said before, its pretty much the same as the RX100 series in capability. The TZ100 has the same form factor and the 250mm is serious reach.
For my needs, which is a pocketable general use travel camera, the TZ100 is unique and can't be beat.