Yes! Had a Facnor main system fitted to our Westerly 33 by Eurospars in Plymouth. As I singlehand most of the time, I found it useful and easy to use. Had no problems with the system, and thought that the single line (one of the main reasons for purchase) was a good idea.
The only problem I had was that the splice in the continuous line migrated towards the mast, and, until I worked out how to get to the roller, this meant that the sail wouldn't furl completely. This was a minor problem, though, and more insight on my part would have solved it sooner.
In common with all these systems the loose footed main and smaller sail meant reduced sailing performance.
In summary, if you don't mind the reduced performance the convenience and ease of use are strong arguments for it.
Great news - thanks. I'm lookng at an Irwin 43 with one already fitted and I wanted to know if I should consider keeping it. Thanks, I think I will hang on to it...now all I need is a new sail!!