what is the difference between all the models? i have an hr 20-700 in my bedroom and living room, Kids have an hr21 and hr22 in their rooms, we have been on whole home for a while using direct connect internet wire into each one from the router. Wanted to upgrade my hr20 in the living room to the new hr24, mainly for looks but hopefully functionality as mine gets slow a lot as most of them do, and to just have new equip. ordered a new one from DTV, they mailed me an HR21, Called back, they said to try and get the HR24 they promised, have a tech come out. He just left, but only had HR22 on his truck. he called his boss and i guess the boss has some so he may come back later today he said if they send him, or i reschedule. Should i just keep what i have-the hr20, or upgrade and hold out for the hr24, or just take any model they have?