Never had a retina in my hands.
I quite like the fed2, and the jupiter 8 I put on it does very well indeed.
Ok, it's not a leica, but it is a lot better than the pokey little viewfinders on the first zorkis and feds. And the diopter adjustment seems a nice feature. Best to stick it down though.
If the rangefinder patch should be hard to distinguish, it helps to put a small round sticker on the front of the viewfinder, right where the patch is (and the same size, of course). You could use a sharpie, if you're brave and precise. That makes focusing very easy, even in low light.
The shutter is a bit limited, 1/30 to 1/500 in one stop increments, but it is the most reliable of all the soviet cameras I have used. It's the only one of them that doesn't mind when you set the speed : before or after cocking the shutter.
There is no accounting for taste, but I say the fed2 is the most beautiful, most racy, most elegant and most sexy of all commie rangefinders, especially if you put some big glass on there, like a jupiter8 or 3.
And people will ask if it is a leica.
A lot more were made of the fed2 than the M3 and M2 combined. About a quarter of a million M3's were made, a bit more than 80.000 M2's, but the fed2 came near to two million. The People's Camera, Indeed. Picasso had one.