One reason this was kind of urgent for us is:

1. The prevalance of low-end Android devices

2. The dominance of Android worldwide, e.g. http://www.idc.com/prodserv/smartphone-os-market-share.jsp shows 2015Q2, android 82.8%, iOS 13.9%, everything else ~3%

We've also been working with Google to see what they can do to make Android/Chrome performance better with complex JavaScript like Ember and Angular. Chrome 45 improved things about 25% which is great, but when you start 500 to 800% slower, there's a long way to go..

Complex JavaScript performance on iOS is, and remains, amazing and stellar. Problem is not much of the world is on iOS.