Inspired by the Brent Simmons interview, I installed the trial of NetNewsWire 3.0 and configured it to sync with NewsGator Online. I used NetNewsWire on the PowerBook, NewsGator Mobile on the iPhone and the NewsGator Beta Online Reader elsewhere.
In the browser
Marking articles as read
Mark Items Read on View - From my previous experience with NewsGator Online, I had high hopes this would evolve to work just like Google Reader where items are marked read one by one, automatically, as you scroll down. Unfortunately, it still works the same as it used to in the Classic Reader. With this option set, an entire page of articles is marked read at the time the page is loaded in the browser. For a feed like BBC News I counted some 25 articles per page. Using this option, if you get interrupted and leave the page, you could potentially lose some articles.
Mark All Above Read - Clicking this icon will mark all news items above the current one as read. This could be used as a marker when leaving the page, as long as the auto mark on view option is turned off.
Keyboard navigation
Navigating the article list by keyboard only works on a page by page level. I couldn’t find any indication how to navigate between single articles using the keyboard alone. No key seems to be available to mark a single article as read, need to click a little check mark icon below the post.

You can move sequentially between feeds or folders but you cannot type a feed name or folder to select it.
River of news
For river of news style reading, you can select My Feeds in the subscription list to display all unread articles from all feeds, sorted with the newest on top. It doesn’t feel as fluid as in Google Reader since you cannot move from one article to the next with one keystroke. The page by page navigation combined with scrolling may be used instead.
Saving news items
Clippings are similar to Starred Items in Google Reader. Adding an article to clippings requires a bizzare two clicks. First, you click the little icon below the post.

Then, a popup comes up requiring a second click.

No keyboard shortcut seems to be available to add an item to Clippings.
Sharing
Not available Google Reader style. You can use email or IM to send a link to the current news item.
Miscellaneous
There are some nice touches such as the many ways to manage a feed, from both the subscription list and the article pane. Search is available, a feature lacking in Google Reader.
On the iPhone
The articles are displayed collapsed, similar to Summaries mode in the browser. Pictures are not displayed until the article is expanded. Paradoxically, the river of news experience is better on the iPhone. Under each article title there is a Mark Read link that, once selected, replaces the article with the next one in the queue. Coupled with the decent summary, the experience is quite fluid.
The subscription list on the iPhone starts at what is level 2 in the online reader and NetNewsWire. Where in NetNewsWire you can select Latest News and in the browser you can select My Feeds to just zip down the articles, they are missing on the iPhone. You can either read feed by feed or, as a workaround, you can place all your subscriptions in a, let’s say Subscriptions, folder and use that one as top level instead. The feed name is not displayed on single articles, so while reading river of news style there doesn’t seem to be way to know the originating feed. At the bottom of each article the time and author are displayed; I would rather see the feed name there.
You can add articles to Clippings but you cannot access the Clippings on the iPhone. You cannot share news items from the iPhone either.