With the added interest from this group, including probably many visitors who just read, plus the new book by Peter Kitchingman, prices probably won't be heading down. At any rate, if you buy a good example you won't be interested in selling it for quite some time, if ever.
If you plan on having the mount changed to Leica M, buy a TV model, and save both an original lens and some money. The lenses appear regularly, both in auction, classified and in retail situations, so it's just a matter of finding the right deal at a good moment. This might be a situation where delay will cost you a bit extra, but my crystal ball is foggy today.
In any case, the lens is worth acquiring, and using, and I wouldn't anticipate much loss if you weren't happy and sold a recent acquisition. It's simply a case of try it, you will probably like it...
Harry
Spoken by someone who already has his lens. :angel: