I like Leica optics, and I shoot Leica rangefinders, but in this particular case, don't believe the hype. In practice, the Nikkor 28 is going to be every bit as good as the Elmarit. In some conditions, possibly better.
The Nikkor 28/2.8 AIS is one of the all-time superstars of the Nikon line. It is so good that Nikon never took it out of production, and still makes and sells them new for about $500. It has very low distortion and it uses floating elements for close range focus correction. It is well corrected for coma. It has few-to-no reflections or ghosts. It suppresses veiling flare very effectively.
It works really well on an FE/FM/F3. No Leica SLR has remotely approached the reliability of the F3. And the FE/FM series of cameras are so plentiful and inexpensive that you can buy a couple and keep one as a backup. The 1/4000 shutter is nice, and even better is the superb TTL flash of the FE2, with 1/250 sync speed.
If you were talking about a 24/25 or a 35, then other systems might be worth considering. None of the Nikkor 35s that I've used could touch lenses like the 35 Summilux ASPH or the ZM Biogons, or for that matter the 35 Summicron for the R system. But for 28, go Nikon.
28/2.8 AIS, 50/1.8E (and/or 55 Micro), 105/2.5 AIS <-- Killer kit.
So far as I can see, there are only two arguments in favor of Leica: (1) Some of the R's have a nicer finder than the FE/FM (but the F3 is afully good); (2) the lens focuses in the same direction as a Leica M (not a big deal; if Larry Burroughs and Alfred Eisenstadt and countless other great shooters could carry and use M and Nikon systems at the same time, so can you).