Dish is definitely proposing to acquire Direct TV although the deal still has to get regulatory approval so it may not happen.
FYI as far as I know there has only been one "scientific" comparison of the picture quality between Dish and Direct TV. This comparison is typically done every three months - the last one was in April. It concluded that "it is quite clear that Direct TV delivers superior PQ". Their previous comparison in January concluded that "Direct TV was the winner in PQ, but it was quite close". One interesting comment in the April test was that both the providers had much improved PQ since the previous test in January.