[SG-]

It won't ever really 'feel' like a native app but it might look like one if you try real hard. My own experience and Facebook's too is that you just won't get the performance and you'll also be dealing with quirky CSS/HTML rendering.

Edit: That's not to say that you can't make an app work, but you shouldn't try to make a typical app using mobile framework that tries to mimic a native app such as jquerymobile or others. If using a non-standard UI it can probably work where the user isn't expecting it to work and feel like a UITableView and every other basic thing in iOS.

[kerrishotts]

I agree -- it is exceptionally difficult to create the look and feel just right in HTML5, CSS3, and JS. I swear that there's an "uncanny valley" for look and feel. To me it is better to bring over some of the "ios"-isms without duplicating the UI (and failing to get 100% right).