I wouldn't say it's "better"; it just has some features which I didn't find in other tools at that time, e.g. translucent cross-links, everything in one fulltext-indexed file, immediate incremental persistence, not speed-down for large outlines, dockable outlines, just to name a few. Didn't have a close look at Org Mode since.

EDIT: of course there are many features which also Org Mode has, e.g. extremely efficient to operate by keyboard (for a trained user), multiple outlines, titles, attributes, not wasting screen space with menu bars and the like, just to name a few.