Every DVR I've ever used, when you add an esata hard drive, it just adds it to the pool of available recording space. If Dish doesn't work that way, I'll have to think hard about whether I want to go that route. I know they have 2TB out of the box vs 1TB for DirecTV, but I can add a 2TB drive on DirecTV and it gives me a total of 3TB. If Dish won't allow it to work that way, I'm still essentially limited to 2TB, because the ability to manually transfer to an external drive really doesn't help me.
When you say the joeys can link to either hopper, do you mean you set that up once, and that joey is always linked to that hopper, or can you change them at will, back and forth between the two hoppers?
To be clear: the programs you transfer to the external HDD means that more space becomes available on the internal HDD for additional new recordings. The best way to think of this is if you have a PC with one HDD as your storage, and one as your record to HDD. You will have acces to both HDD's to playback or transnfer (yes, you can transfer a recordings BACK to either the original HDD or antohter DVR' HDD that is on your account) if you wish.
Further, the HDD strorage can be accesed for playback by any paired Joeys, and the strorage HDD can also be connected to any ViP Dish DVR (non-Hopper/Joeys) on your account allowing playback in other rooms that may not include Hoppers/Joeys except for the ViP 211, which actually does record to the external HDD.
You can create an UNLIMITED number of Storage HDD's. For example: One HDD for movies, one for the kids shows, one for your shows, etc.
Competitors either span the new recordings across the internal HDD and external HDD so that when your internal HDD dies you lose all the recordings on the external one or don't allow any transferring to an external HDD which means you will LOSE all your recordings on the internal HDD when it dies, and that is the worst solution, at least for me. Also, if you think the internal HDD is goint to die, or you want to SAVE recordings from possibley being LOST when the internal HDD dies (and they all DIE), with Dish you can transfer recordings to the external HDD for SAFE KEEPING.
Overall, I've found the Dish "Archival HDD" system superior, especially by allowing me to SAVE PRECIOUS recordings of show or movies and I've save all my recordings after noticing behavior that foreshadows an internal HDD failure so that when it does fail, I have ALL my recordings on the strorage and didn't lose a one when the internal HDD dies. You can then transfer them BACK to the new DVR internal HDD or leave them on the external HDD and playback from there.