XD 8.5x44 Prominar (Genesis)

I've had a pair of the 10.5x44 Kowas for 9 months. Almost immediately, though optically excellent, I found them very (too) heavy - I'm over 6 feet tall and no lightweight! After a morning's birding my back and neck were aching. Using them almost daily, I soon found that the focussing mechanism became very impreciseas if it had become worn very quickly, making it difficult to "find" some birds, particularly those moving rapidly. By the time the binoculars were in focus, the bird had often gone. Depth of field on the 10.5x44s is also fairly poor. Another mechanical fault which has arisen more recently, again adding to the difficulty of locating birds, is that the rotating eye cup on the left eyepiece now winds itself down as it rubs against my jacket. This means that, at times and without my being aware, one eyepice is correctly set while the other isn't and has to be repositioned. Once again, birds are missed by the time this has been done and the bins focussed. I'm hoping that these problems will be covered by warranty but, overall, I wouldn't recommend these Kowas. There's plenty of room for improvement,particularly on wight and durability.