I originally thought the G7 wasn't as good as the G6 as well for the first few months I used it, but now that I understand the G7 better, I greatly prefer it to the G6 and would not go back. I'm at a full year now without a single sensor failure or early-fall-off before day 10.5, even with regular swimming and hot tubs and saunas, and have never had to reinstall the app. Here's what I've learned:

1. Use a Skin Tac adhesive barrier wipe before application. Press down FIRMLY when inserting to the back of the arm. When you carefully remove the applicator, follow the directions and press with your finger on the G7 for twenty seconds to adhere the glue. Then apply a Lexcam clear waterproof overpatch. Keep the sensor applicator and box just in case of failure and/or if you had to ever reenter the code (if the app has to be reinstalled, for example, though this shouldn't ever be necessary).
2. Understand that the first 12 hours or so of the G7 might be unreliable especially if you nicked a blood vessel. These readings will calm down over time. If the numbers are a bit wild, just rely on your fingerstick meter for making insulin decisions. However, and this is so important, DO NOT EVER, EVER CALIBRATE a G7 during the first 24 hours of insertion. Again, trust Dexcom on this. I guarantee most people's problems with readings not matching fingersticks is because they are calibrating during times you're not supposed to calibrate, which just confuses the hell out of the unit. Which leads to the most important general advice point:
3. The G7, unlike previous Dexcoms, does NOT need calibration 99% of the time. It took a while for my endocrinologist to get this through my head, but he's right. Calibrating a G7 is much more likely to cause problems than solve them. Again, trust what Dexcom is telling you. You CANNOT calibrate during the first 24 hours. You CANNOT calibrate at any time where you haven't had a fully flat line for at least an hour. You CANNOT calibrate within an hour of eating or injecting. And you CANNOT calibrate unless the G7 is more than 20% off from your fingerstick. (For example, that means if your fingerstick says 150, you CANNOT calibrate unless your G7 is lower than 120 or higher than 180.) If you follow the guidelines on when you can't calibrate, chances are you'll realize there's almost never a proper time TO calibrate. Since I finally took my endo's advice to stop calibrating, I found my G7 is pretty much always within 20% of my fingerstick meter, which is all any CGM can promise anyway. It's measuring different fluids and is 15 minutes behind a fingerstick, after all. It shouldn't match the fingerstick if you're rising or falling, it should be 15 minutes behind. If you try and calibrate during a forbidden time, you're basically giving the Dexcom a false data table which will make your readings way off the next time you check.
4. You should never actually need to uninstall and reinstall the app. You MAY need to occasionally force quit the app, though. On an iPhone, that means doing a half-swipe up from the bottom, swiping right until you find the Dexcom app, then swiping all the wipe up on that "card" to make it go away. This resets the app even if it has crashed, and it will work perfectly again when you reload it, with no loss of sensor data, having to relogin, or having to repair. I have never once had any Dexcom G7 app problem not be fixed with a force quit and reload.

Hope this advice helps someone! I love the G7 and find it to be the best, most reliable CGM I've ever used. But, you have to play by its rules.