I'll mix it up here. My vote is for the 3904 simply because it is the final interation of the original pre model 39. It's great to pull out the pre 39, 39, 39-2, 439 and 3904 and admire the evolution. Alloy frame, single stack, blued, 9mm with fixed sights. With all of the love for the 3906, its weird that the 3904 doesn't get a lot of hype. I'll never sell mine. Even though its not recognized yet as an icon, it could further down the road.