I've been using the T-Mobile 256kbps free data all over the world for the past few years and find it adequate for mapping, navigation, email & texts. It does depend upon the carrier you are using though. Sometimes the automatic choice is not the best or fastest, so if you are getting poor service you can generally find another carrier that is better. I also use off line maps on occasion, (I Like Pocket Earth Pro) but generally find that the Apple Maps works well enough. Plus you get free FaceTime Voice or Video calling to others with iPhones in the same country.

I do experiment with the less expensive data services, so I am currently evaluating Airalo and Stork for my upcoming trip in the Spring. I'll only drop $10-$15 and hopefully find another cheap alternate to the free roaming data service.