How well have intents actually worked out in practice on Android? It's been awhile since I spent much time with an Android device but a year or so ago it was very rare that I really wanted a generic utility.
Where I've not see so much use is providing completely new intents, presumably because its so hard to get any sort of agreement on how they should be implemented.
Additionally for the big system-level intents there is an "always use this action" which is useful so you don't have to repeatedly tell it to use the phone app to place phone calls.
Sadly, the Google+ client doesn't share out yet, but hopefully that's coming.
One of the finer points which I really appreciate is how intents can be fine-tuned not only to handle "a image" or "a mp3" or act like a extension/protocol-handler in your desktop OS, but how it can react on parts of a intent, like the domain of a URL.
When someone links to Applications on Android market on a web-page (i.e., a https-link to market.android.com) and I click it on my Android device, I actually get the link "opened" by having Android market app launched and focused on that specific application. Very, very neat.
The same thing can be done for wikipedia readers. A wikipedia link launches your app. In the same way other apps can provide intents for music selection, playback, data-sources, data-consumers and god knows what. Or just have an app become the default for some action on your system by handling the generic intent (i.e. surf the web).
Intents are one of the really good things which makes Android Android. And in case there were any doubts: I think it works out bloody fantastic.