I'm finally sick of Verizon's shit to the point that I want to switch. They're expensive, nickle and dime you on buying phones, heavily lobbied against Net Neutrality, and refuse to sell a phone without a locked bootloader.
Project Fi is the one that I keep coming back to, but I'm not 100% sold.
Basic plan is $20 for unlimited calls and texts, plus $1 per 100MB of data usage (so $10 per GB). No contract, so you're only charged for what you use, and they cap your bill at $60 for a given month without cutting off data. It also uses 3 networks (Sprint, T-Mobile, and U.S. Cellular), and will jump to whichever tower is strongest at the given moment.
But there are two things that give me pause. The first is that there have been some complaints about phones leaking data, with some folks seeing a generic "Android OS" entry taking up 500MB-1GB per month. Now I haven't seen any reddit posts about this within the last 8 months or so, so this may be fixed.
The other is that it doesn't seem like you can root a phone or switch to a different OS without potentially screwing up service. This is a mixed bag: I'm actually trying to get away from Google as much as possible due to their data collection. Granted, nothing says I have to use GMail (and I'm moving towards not using it at all), and some of the more egregious things (the various services that involve always listening) can be disabled. And I'm not 100% sure there's a significant difference between giving a lot of this data to Google vs. giving it to Verizon or some other carrier. On the other hand, even if I'm not using GMail for e-mail, your phone is tied to your GMail account.
But I'm also not sure what the alternative is. Verizon sucks as I said, but the only other companies in the same ballpark price-wise as Fi are these smaller no-name ones, and it's a roll of the dice either way.
I've been with Project Fi for over two years, and on average I use about 2 GB of data of month. I pay about $50ish per month.
I originally got an LG Nexus 5X and it lasted until about a few months ago when the phone's dreaded bootloop issue killed it dead, so now I have a Moto G6 (I like that recently they've expanded to a wider variety of compatible outside phones: Originally you basically had to order a compatible phone through Google since there were only 2-3 varieties, but now you can buy a qualifying unlocked phone in any store).
I only mention the phones to say that I've never had the issue of Android OS using 1 GB of my data, and admit that it might be a product of what phones I used. But I also kill nearly all notifications on my phone, as well as disable a lot of default apps. The only major data hogs on my phone over time have been Twitter and Facebook, and that's all on me.
If you've got understandable hangups over Google's collection and usage of data, I can understand that. It might not be the best move to take on a service run by Google if you've got those reservations, when they have their claws in Android OS and practically mandate their apps be all over the OS.
But I personally have little shame and couldn't care less what of my data they have, especially since I have Gmail and they pretty much have all my info through there anyway. I disabled most of their data collection on my main Google account, and really only enable GPS on the phone for various personal reasons.
That aside, the service has been terrific. No frills, not expensive, and super reliable. You can even use data as normal outside of the US, though calls still cost extra. If the Google privacy concerns aren't a dealbreaker, it may be worth it.