Joeys pull a tuner from the hopper. For 2 tvs a hopper3 and 1 joey would be the best scenario. The hopper3 has 16 tuners, the joey has no tuner. Joeys are basically an extension of the hopper.
With 2 tvs, hopper3 and 1 joey. You could have 2 tvs doing 2 different things and be recording 14 other things all at the same time. It is a great setup, many here will attest to that. As a new customer you would be way better off money wise than you are now with Directv and have superior equipment.