The other two are Crystal Space and Ogre. There is no real shoot-out of the three engines, but a feature list and a detailed description of the pros and cons of each library.
Irrlicht gets pretty good results (who wonders
). Remarkable points in the feature comparison (top-down from the table): free license, directX8 support, software renderer, many mesh importer, collision detection, versatile particle system, water scene node, many animation types.Things missing: Sound, exporter from 3d modelling tools (they even did not knew about the .irr format at the time writing), few shadow techniques, no Cg.
the detailed report highlights the small memory footprint of Irrlicht and its speed, as well as the software renderers which make it suitable for embedded applications. The Ogre loader is explicitly named, probably due to Ogre being also part of the report. irrEdit is shortly mentioned, maybe due to the original topic on game engines (which all three aren't really).
The overall result for the two other engines is that CS is only used in academia and thus not really relevant. Ogre is used in commercial games and has good integrations into commercial 3d modellers. But the separation of several features into modules makes it more complicated to use all features, and many features are also available in Irrlicht. Moreover, Irrlicht is considered more active and with a decent potential
Ok, before I write down the complete article and come into legal issues: Buy it if you understand German
And welcome the new Irrlicht users that will show up due to this report 