MY concern would be how long it would work. Legal or not, you are decrypting Dish Networks data and they could change the scheme at any time, although it might not be likely if it messes up their 'real' customers programs.
I used to live with someone who had a something set up to grab DirecTV and it seemed to work for a while then DTV did would tweak their signal and you would lose everything until you dowloaded the new key. IT finally got to where this was happening two or 3 times a night and made it not worth it.
Dish is currently broadcasting 90% of their stuff in Nagra1. When they switch to Nagra2, which could be next month, next year or god knows when, owners of these devices will get nothing.
Nagra2 has been broadcast in Europe for 5+ years and never decrypted. It just depends on how you feel about spending hundreds of dollars on equipment that may be virtually useless in a matter of weeks/months.