Huh, did you really run iOS9 ad blocking on a Motorola Defy? I definitely believe Apple's position is 99% marketing, but I can imagine there are some common pages that load really slow on older hardware. I've seen older iPads crash consistently trying to render complicated pages.
Of course I did not run iOS on that Defy, why would I? Ad blocking was everywhere before apple finally decided to allow it on iOS. Inside those idevices are ARM-based CPUs, just like the ones in most other mobile hardware. What difference does it make whether the OS is based on Linux (Android), Mach/BSD (iOS) or even Windows (...Windows)? A regexp is a regexp after all...
The Defy does not crash rendering complex pages. It can get pretty slow though, reason for running extensions like NoScript for Android [1] (which runs just fine on the Fdroid.org Fennec build, ie. Firefox without the nasty bits) and uBlock origin.
