Yeah, the promise is not "write once, run everywhere". It's 1) write in a familiar way and 2) reuse a substantial amount.
The only place that I usually end up making platform-specific changes is where Ionic has an iOS-specific layout change that breaks the look of a custom component on iOS. That and sometimes native-only features like Push Notifications that need to be handled slightly differently on each platform. But the latter is about a half dozen lines of stock code that take the iOS result and hand it to a common handler.
I'm probably sticking with Ionic for now, though I'm planning to try out Meteor for my next project that has backend requirements. Meteor can install the Ionic SCSS as a plug-in, so you CAN get the best of both worlds.
Ionic is using HTML widgets , not actual IOS or Android widgets like React Native , Titanium or others. So you are basically developping an HTML client inside a webview and calling it an APP. Of course you'll be able to reuse 98% of the code that ran into a web browser. But it will look like an HTML website.
This is simply not true anymore. For simple CRUD apps, our customers can't tell the difference between a native app and an Ionic app. The ionic team has done a great job simulating the native animations and interactions of iOS and Android.
If you don't believe it just try it. It costs 30 secs to install Ionic via npm and deploy one of the demo apps to an Android or iOS device.
For more complex apps I'd consider using a native framework tho. As usual it all depends on the use case.
There are dozens of platform-specific styles in the CSS that make each target behave more like a native app. A custom-styled native app, but one that follows platform conventions.
I also absolutely abhor the fact that React mixes HTML with JavaScript. It just feels so completely wrong to me.
React Native is much more a step in the right direction IMO, although the Ionic team's work on Ionic 2 with Angular 2 could provide an interesting paradigm to compete on that front.
React Native has been absolutely amazing so far. So excited for Android!