The downside is Dish may not activate it.
Currently the 522 is for lease customers only, hence Dish owns the equipment.
Some people have had luck getting the 522 activated, BUT the 522 has to be brand new, never activated, any you must be a certain grade of customer to Dish ie how much is your bill and do you pay on time.
Contact
ceo@echostar.com to see if they will activate it for you before you buy.