Is it the same? It is a satellite-based service, the same as DirecTV, but Dish is not affiliated with DirecTV. So, yes, you could cancel Dish and go to DirecTV, it would mean scrapping all your receivers and dish and having all new equipment installed.
There are a great many discussions here as to who is better, but it comes down to opinions based on the different offerings of each company and the quality of their signals.