Note: I'm assuming Managed Workflow with Expo to leverage the max out of their services.
Expo : The Good
+ Great for boot-strapping react-native development for cross-platform mobile app development.
+ Possibly a good choice for PoCs to quickly showcase a concept.
+ We get to see the console logs of app in Expo's browser or terminal. This one is a big plus!
+ The documentation is good but could be better.
+ Expo's snack is the code playground in the web browser that will come handy when you want to try out its components from the web-browser and see how it appears in android/ios/browser, before you use it in your project.
+ Leverage Expo platform for sharing the app in development to Business to get their feedback and adopt accordingly. Agile isn't it?
Expo : The Bad
- Limited choice of reusable React Components that has dependency on native components. Expo is getting better by the day in this, though!
- Their free build service is time consuming (you number in waiting queue could be over 20 with waiting time of over 20 minutes) and paid ones are way too pricey.
- Not all iOS and Android APIs are supported. That said, a great chunk of most used APIs are supported, except for things like Bluetooth, or WebRTC if that matters to you.
- No support for background audio with OS playback controls.
- Doesn't have FastImage incorporated into it and guess is working on its own version of FastImage, calling it expo-image. For the uninitiated, FastImage is to ReactNative, what Glide is to Android and SDWebImage is to iOS; it is a performant image loading and cacheing library.
Expo : The Ugly
- The app size is no less than 60 MB by default. You can reduce about 20 MB by using a property like `enableDangerousExperimentalLeanBuilds: true` in `app.json` for android; but that still keeps the app over 40 MB, which is ridiculous in my opinion. So where your app could do away with just 4 MB in plain Android development, using Expo is an epic failure.
- Expo by default adds way too many unwanted and unwarranted permissions as requirement to the app being published. For instance, it by defaults adds requirement for camera permission. In days of malicious malware being shipped with apps published even in Play-Stores, this will only raise the users' suspicion discouraging them to try the app.
- Connection to Expo dev server gets disconnected after some idle time hampering your hot-reload functionality. When this happens, you will have to reload the app. I experienced this quite often, and it is annoying.
My Verdict
Productivity gained in one thing, is lost in many other things by using Expo. Expo is beginners friendly entry to embracing React Native and may be do a quick PoC. Until things change for better with Expo..