[emmett]

Perhaps a binary or ternary order of magnitude, rather than a decimal one. 10x is probably an exaggeration I would say typically it's more like 2-4x.

As I'm not an expert iOS programmer, I'm not exactly sure where the overhead comes from. Given the bugs that are usually present in iOS apps, the tricky bits appear to be:

- Handling screen reorientation

- Making scrolling smooth (it's easy to load either to lazily or too greedily)

- Making it feel "snappy"

- Not segfaulting when you have an error

The web executes on hardware far faster than mobile does so you have a lot more leeway to be sloppy. Ditto for the fact that web apps can't segfault, and it's hard to actually crash a browser.

Another really important point: Doing things on mobile is easy, almost as easy as the web. Doing things WELL on mobile is much harder comparatively because the platform is lower level and less powerful.