Irie, Inc.

The scenario is this: I am adding a new story to an existing group of stories. How do I make it a part of the group as I create it?

Analog (3×5 cards)
Write the story on a card. Set the card on the appropriate pile.
Usability: High Downside: it may be hard to find the right pile if you have too many of them (no search feature)

Ideal Digital Tool
Find the group and select it. Create a new story card. By default, the selected group is the parent object for the new story, though I can always change it. OR, create a new story card without selecting a group, can select a group from the creation screen.
Usability: Very High

AgileOnDemand
Select the Epic or any story within the epic. Add a new story. The new story is automatically in that epic.
Usability: High Downside: there is actually no way to add it OUTSIDE of an epic unless you first select a story that is not in an epic, which is not self-evident.

Rally
Locate the object that will be the parent, and click the Add Child link. Save the new story. Or, if you click the New User Story action, then you need to select the Parent field before saving.
Usability: Medium-High Downside: no concept of ‘context’ for the Actions menu, and no right-click menu, must click the correct button on the far right.

Excel
Jump to the bottom. Create a new record. Make sure you populate the Group field correctly.
Usability: Medium-High Downside: Gotta spell the group correctly, though filtering before adding makes that easy

VersionOne
Add a new Story. In the Feature Group field, select the parent grouping. Save.
Usability: Medium Downside: no concept of ‘context’. In fact, the Feature Group tree is seldom viewable as a tree, and never with inline stories.

Mingle
From the Tree view, click the Add Child link for the parent object. In the popup, enter the summary for the story. Then, find the newly created card, and click it to display a popup. From there, click the Open link (yes, you can’t double-click it or otherwise edit in one operation), and from there you can enter the user story text. OR, from the List view, if you Add With Details, you can find the relationship field (it’s not obvious, it’s marked: “Feature – Epic Story”) and click the (not set) link, click ‘Select’, then use the filtering tools to find the story to make the parent.
Usability: Medium-Low Downside: too many clicks caused by the fact that this is a generalized tool – powerful, but not optimized

Usability Comparison Summary on a scale of 1 to 10