When to use UIWebView versus Safari in iPhone App?

When displaying web content within an iPhone App, we can generally choose between displaying that content within a UIWebView, or popping open an instance of Safari.

I've generally found that for related content, the experience of displaying the content "in-app" by using a UIWebView is cleaner (maybe in a modal view or navigationcontroller), though it's a bit more work to do so.

For possibly unrelated content, I'll generally go for Safari.

Is there any established开发者_运维知识库 line of reasoning for picking one method over the other?

EDIT: Along with the technical, what's your reasoning with respect to user experience?

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Last I read, Safari will execute JS much faster than an embedded UIWebView. The UIWebView, as it is used in user-generated apps, will not precompile the JS for improved speed.

It looks like this deficiency may go away iOS 5.

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With respect to the UX, I think it depends on when the web content is displayed to the user in the user's workflow. Also, how frequently it is done & how distracting it can be? These things matter because you want to keep the user inside your app for the maximum amount of time (there is a good chance that the user won't come back). It is frustrating for the user if she has to leave your app to go to Safari multiple times & return back to your application within a short span of time. Moreover, if by any chance you have specified that your app be terminated if it is sent to the background, then you should not be launching Safari.

For example, the same factors hold when you create you Settings page. To quote from the HIG,

Applications then have two options for presenting preferences:

Display preferences inside the application. OR

Use a Settings bundle to manage preferences from the Settings application.

Which option you choose depends on how you expect users to interact with them. The Settings bundle is generally the preferred mechanism for displaying preferences. However, games and other applications that contain configuration options or other frequently accessed preferences might want to present them inside the application instead.

HTH,

Akshay