Im watching on a calibrated 64". Dish is slightly softer than Directv, but Dish seems to have more vibrant color.
IMO, Directv looks better, and most people that switched have commented the same, but it's small. Where Dish suffers is the compression at times, and thats just because they are cramming too much on a TP IMO.
Id compare it to Vudu HDX and Blu-ray. HDX looks great, but if you watch bost, HDX is noticeably more soft than Blu-ray. But, its not a deal breaker because they both look good, one is just better. Its not a bad vs good thing.