Incidentally i spend the last 2 weeks going through various Android devices, and iOS devices, various javascript frameworks and various CSS frameworks.

I'm happy to see others having opinions on this subject.

Essentially i did the research for these combinations:

[Android devices]x[iOS devices]x[js frameworks]x[CSS frameworks]

It was hard and tiresome but the conclusion - same as yours - iOS works very well for cordova/phonegap. Android is a no-go!.

Among the frameworks I checked: backbone, ember, angular, ionic, topcoat and various other CSS frameworks.

All were slow on Android. Also discovered 4.4 introduces worse performance (acknowledged by google) which is solved with crosswalk. However crosswalk brings many bugs to the table itself.

Really disappointing - currently I'm opting out and going Native.

Allow me to suggest taking a look at QML/Qt Quick. I've only recently started working with it, but so far the UI performance is excellent and for someone experienced with HTML/CSS layouts and JavaScript it's quite easy to pick up. (Also, FWIW, it's more enjoyable than twiddling with CSS.)

Maybe I'm a moron, but the entire concept of "native look and feel" means nothing to me. I have used android for about 5 years and have played with plenty of iOS devices and I'm still not sure what parts are native. Apps all have seemingly different look and feel. We certainly never sweat nativeness on the web going for consistency across OSes instead. It seems like going to native look is not even a desirable thing.