I've noticed that only @replies to mutual followers are being shown currently. I'd prefer the default was to show these, just like the main twitter website, or have an option to enable them.
From the userstreams documentation:
"By default @replies are only sent from mutual followings. All @replies by followings can be enabled with the replies=all parameter. For example, if Alice follows Bob, but Alice doesn’t follow Carol, by default if Bob @replies Carol, Alice does not see the tweet. The default behavior mimics www.twitter.com and api.twitter.com behavior. If an application wishes to display all @replies, or a filtered subset of @replies, use replies=all."