I've only had mine for one season but am very happy with them. This past season I had a chance to sit in a stand with a friend who had the Swarovski 15x56's. I found the Swaro's to have a little better color definition and were a little brighter but the Leica's had a greater depth of field. Seemed to put you right out there where you were looking and get you involved more than the Swaro's. Very comfortable for extended viewing.
They are a little heavy but with a bino harness like these
they are not a problem at all.
Mine would range almost anything out to 1000 yards without fail as long as you could find a reflective surface. Finding a good reflective surface is something you have to do with any of them.