I have ported a game on iOS and Android approximately two weeks ago, so let me share my experience with you.
If your game is under 50mb then:
For Android:
You can use Cordova export in C2 and build using Ludei Cocoon . When building you can use Canvas+ Webview engine, that gives a very good performance, but adds a splash screen (you can try link in my signature to see both performance and splash screen). If that is a no no for you, then you can go for Webview and Webview+ - they do a fairly good job as well without adding a splash screen. Ludei has a very nice blog post about these engines and what they support, take a look at it to save yourself surprises later on.
For iOS:
I exported the game as HTML5, and build it using Webview engine in Ludei. That was the only working way i have found. Performance was good, but there were a couple of issues with sounds (namely, autoplay, and mute) and video (they would open in native iOS video player), that I am yet to fix. One more thing - you will need a Mac to upload it to App Store (or just emulate Mac). Btw, passing your game to iTunes Connect standards is quite an adventure too!
If your game is more than 50 mb you got to go for a paid plan in Ludei's Cocoon or, go for Construct 3 that has direct exporting options, with no need for third party builders. I have not tested it yet myself, but rumors are, it is pretty good. One thing to note though - some plugins that you have used in C2 might not work in C3, so watch out.
There are other options there, namely Phonegap by Adobe - with which, performance wise, I got terrible results and Intel XDK, by Intel, which I havent used myself, so lets hope someone else will provide intel on (see what i did there?)