you can try running my hardcore game in browser on android / ios, here's the link:
https://dl.dropboxusercontent.com/u/136 ... index.html
just turn debug in options to see framerate / cpusage (it's around 80MB so prepare for a long download <img src="{SMILIES_PATH}/icon_e_smile.gif" alt=":)" title="Smile"> )
it got everyhting for testing purposes, lots of enemies, particles, moving stuff, tiled sprites, and more.
speaking generally of performance it's good, crosswalk improves xdk improves, you can even use visual studio to build your games and so on.. things are moving forward fast .)