Disclosure: I left Dish for FIOS already.
One of the reasons I left Dish was because of price. (Other was unreliable internet) I wanted a "whole home" DVR and HD on each TV. I'm not griping about that, but to do that was expensive (comparatively). I'm glad to see that Dish is working to deploy this Joey/Hopper system and think it is a big step in the right direction if they get the pricing right.
A suggestion would be to allow people to buy the Joeys and not charge a monthly fee for them. You could still let people rent them for $3-$6, but encourage people to buy them outright. Rent the hopper as the first DVR on the account and include it like you do now.
If you encourage people to buy the Joeys, they will be less likely to switch. They will already own equipment and feel like they are invested in their choice. Maybe work out a deal with someone like Roku to even add Dish to a model of theirs. I would have loved to have a Roku box with a coax input or just IP streaming that would work with Dish. But the main idea is that you enable people to save a little money in the long term.
As for renting, you should consider the model that FIOS has. I have a main DVR and three STBs now. I originally started with two STBs, but FIOS gives packaging prices for getting more. ie, DVR + 1 STB, DVR + 2 STBs, ...etc. Every time you add another STB, you get a slight discount on the package. Its not a lot, but at least I feel like I am getting a deal.
Just a thought.