Rough translation of the XTension review:

Mac Fan has published a few pages on home automation.
Page 50 says about XTension:

The web site of XTension gives the impression that the author hasn't given it a second glance after 1996; Who dares, in 2009, using images that seem to originate from the Microsoft Office Illustrations gallery? And don't these alternating blue and red lines in Times New Roman font hurt your eyes? Developer annex NASA employee Sand Hill fortunately admits: his application is an oldtimer. But an oldtimer that is improved and extended daily.

Because of the complex layout and the lack of simple operation, XTension is not an application for the big audience. On the other hand it allows for an almost unlimited number of configurations. This freedom is especially interesting for the very advanced user who wants to squeeze as much form the X10 installation as possible. The layout of the app resembles Indigo, but every time it is just a little less intuïtive.

XTension offers a wide range of ingenious functions, such as a built-in web server , communication through Applescript and a dedicated iPhone companion. Finally, it not only works with X10, but also with the less well known Dutch protocol KlikAanKlikUit. And, also important, as the application supports all Macintosh operating systems (from OS 7.1 from 1992 to the most recent version of OS X), you can even use it on that old dusty mac in the attic.