In documents with multiple columns, you can drag on the screen with one finger to reposition your view and expose columns that appear off the screen. As with the previous version, you can restrict the data types used in the columns, such as limiting a column's cells to just numbers or dates. (And I appreciate that the app is smart about its data, letting me type something vague like "Friday" into a cell and automatically converting that to the correct date.)
When scrolling down through long documents, the app still needs to occasionally pause and load more content (as it doesn't load the entire document into memory), but this feels faster and less obtrusive than in the original version.
Repositioning rows is a simple matter of drag and drop, with a visible guide that indicates exactly which outline level you're targeting.
As you're creating a new row of data, it's simple to indent or outdent the level using buttons at the lower-left corner of the work area — which just happens to be where your left thumb is positioned while thumb-typing on the iPhone's screen.
I did run into one anomaly: When adding new rows to the bottom of an outline, the cell is initially hidden behind the document's headers, but it pops into view when you begin typing. (I reported that to the developer.)
Not long ago a "mobile" version of an application didn't carry many expectations; it could get away with just viewing documents. Now, however, we expect not only editing but a way to make the documents appear wherever we are, with as little friction as possible. OmniOutliner takes full advantage of Omni Sync Server, a free service the company built from scratch when it became clear that iCloud wasn't going to work for them. You can also sync using your own WebDAV server, or add outlines to the Local Documents storage area via cumbersome iTunes sync or by transferring a file from another application using the iOS Open In mechanism.
In my experience, Omni Sync Server is the model of cloud syncing. When you update an outline on the iPhone, for example, the edits are reflected on the iPad and in OmniOutliner 4 for Mac within seconds, even when the document is open on all the devices simultaneously.
If a document is edited in two places before they're synced, the server displays two copies, with the source added to the title, such as: "Test Outline (conflict from mobile on iPhone 6)." Although I'd love to see a way to highlight differences between the documents, it's a nice touch that when you delete one version, the file name reverts back to the original and doesn't litter your documents list with messy conflict names.
Sign up for CIO Asia eNewsletters.