Yes, I have a topdown Selden furler with an asymmetric of around 65 sqm. Originally the luff flew free from the torque rope as is common, but I found that on my own it was tricky to get the furl right and on 2 occasions a fold caught in the furl resulting in not being able to unfurl it. This happened in stronger (10+ knot ) winds where you need to balance the tension on the sheet with the furling line as you furl. If the luff backwinds just as the furler catches it, then the fold starts. Unfortunately you can't tell as the furl seems normal. The only way to unfurl it is to take it off, stretch it between 2 fixed points and manually unfurl it so that you can unpick the folds.
After discussion with the sailmaker (Kemps), they recut the luff a bit flatter and attached it to the torque rope over the whole length. Only got a chance to try it once last year and the change certainly seems to have worked - much easier to furl as you don't have to concentrate so much on getting the furl started. Having said all that, the most common setup is a free flying sail, so obviously others don't have the same sort of problem.
Presumably you already have an asymmetric and a prodder or other means of tack attachment so will just need the furler. This is around £2k, and I suggest you also buy the Selden stanchion blocks and double fiddle cam block (£300) to lead the double furling line back to the cockpit. I have the fiddle block attached to the pushpit eye with a snap shackle. This bit works very well. As an aside I have a similar setup for the jib furling line using a Harken cam block attached to the pushpit as I found the standard deck mounted block difficult to use. You would need to get the sailmaker to fit your existing sail to the furler, so I guess total cost is going to be £2500+
Is it worth it? If I had an active crew who did not mind foredeck work, I think I would stick with a snuffer. On the other hand making such a sail easier to use means you are probably likely to use it more often.
