No, but I'm planning to take some pics, it's just arrived....sometimes I think it would be better to spend my money on the Russar Mr-2 but probably the Orion being coupled is easier to use.
If you speak Italian or you have a good online translator you can read this page on the history of Soviet wide lenses, their use and the comparison with Leica's, it's pretty informative:
http://www.marcocavina.com/articoli_fotografici/Soviet_and_wide_lenses_on_Leica_M/00_p.htm
In short the Soviets developed indigenous designs like the Russar and the Orion for pure military reasons ( air recon, later spy satellites etc...) and they adapted those designs to the civilian market...BTW the Orion-15 was used in that interesting KGB device that you can see in the pictures: I mean the suitcase with inside the camera that was "left" on the documents the Soviets needed to copy.
Compared to the the Leitz wide angles the opinion of the author (excellent photographer, BTW) is that the Jupiter 12 is excellent, the Orion-15 is handicapped by the 5.6 aperture (it would perform better if it was faster) and the Russar is softer at the center than the Leitz 21 mm but sharper on the edge so the photo quality is "comparable".