Just had my old HR21 replaced with a Genie and everything with the install went well. I now have two HR22's, an HR24 and the HR44-700. The installer replaced my SWM 8 with a SWM 16. He also replaced a couple older cables with thicker RG6 and capped off some old cables when once upon a time two were needed for each receiver location.
The Genie is incredibly responsive albeit the remote takes a little getting used to. The swap-out took about an hour, but a lot of that was him checking the other receivers to make sure they still received signals, etc. I was very pleased with how it went and am happy that I can record 11 shows now at one time. LOL. Just thought I'd share a successful upgrade story.