The 21mm lens is the only rangefinder lens I use that isn't a Leica (the 28, 35 and 50 I have are all Leicas). Great quality for the price, with an awesome finder. You can find them for less than $400, which is about the same price as just getting the Leica 21mm finder without a lens. However, I have nothing to compare it on, but with the quality I have seen from it, I can't find a reason to go beyond it.