Just wondering which is faster in terms of performance and usability? Or if there\'s anything better out there?
ASIHTTPRequest is just so much better than NSURLConnection it's ridiculous. It's more powerful AND simpler. I recommend it pretty much every time I see a question here related to NSURLConnection.
I don't know of any other http client library. I'm not religious about ASIHTTPRequest--if a better tool came along, I'd use it. But ASI has SO nailed it, it's hard to think of anybody else reinventing that particular wheel.
EDIT Feb 2012: As of a few months ago, ASIHTTPRequest is deprecated and its author recommends using something else. AFNetworking seems a popular choice, though I haven't used it personally.
I mention this here because this question and answer remain popular, and it seems people don't know about this change.