A few years ago, I learned that, on an iPhone 5s with the latest operating system, Google's map app required three times as much data as Apple's. I learned this because I paid fifty dollars for five hundred megabytes of data over two weeks in Asia and, since I was relying on my phone for everything from finding out where I am to ordering in restaurants, by the time I was in Taipei I was sipping data in thimbles trying to stretch the last hundred megabytes over the next three days in what ended up being the saddest Channukah-style miracle of my life just to avoid paying foreign roaming fees. I did not read the contract that closely, but I'm pretty sure it would've been cheaper to light my house on fire than pay data overages abroad. I will not specify my wireless provider at the time, although I will mention they're near the front of the alphabet, but I was out of contract a month later and decided I needed a new cell phone service.
"You are now in Denmark. Texting is free. Phone calls are $0.20/minute. Data is $10/GB." IIRC this was the message my phone sent me when I turned it on upon landing in Copenhagen, my first trip abroad having switched to Google's cell provider, Project Fi (URL for referral link here), which I hope is the last cell provider I ever use.
Here's an example why.
When I first switched over, I was visiting a friend in Bellevue, Washington. In Bellevue, Washington, there are very few stores that are open late, so when my cell phone stopped charging and was down to 10% and I didn't have a laptop with me and I needed my phone to get to the airport and then on the airplane, this was a minor emergency. Ultimately, the answer was "turn the phone off and turn it back on". But when I requested help from Project Fi customer support, I sent an email and less than ten minutes later someone called me, in the evening on a Saturday. All of my interactions with Fi customer service has been like this, and compared to the other providers this alone is fantastic.
Here's another example.
Once my phone (a Nexus 6p with 120 GB that I bought mere months before Google released the Pixel) is paid off, my monthly bill will be under $30/month, whether or not I spend three weeks abroad using maps in Singapore or checking email on a train in Tuscany (lol j/k there's no cell service in rural Tuscany) or watching YouTube videos in a park in Vienna.
Between the low base cost, flat rate data plans (that refund unused data (!!!!!)), the reliable service (switching between the Spring or T-Mobile networks, or VoIP on wifi, depending on what's going to work best), and the staggering customer service, I very much hope that Project Fi is my last cell phone provider.
Edit the first: I spent 80 minutes on a phone call to Spain and it cost $2.55.
Edit the second: My Nexus 6p just died, and Fi is replacing it with a Pixel XL at no charge, and overnighted it.