Channel logos take up memory, and my personal experience with Direc TV boxes that had channel logos was quite negative as they were constantly updating and lagging in display modes. I had channel logos with cable, but their implemention was also very poor: logos too small to see well, and I didn't like it. I have a TiVo and thier channel logos aren't so hot either because they don't display on either EPG's, only on channel banner and list of recordings, and I NEVER need nor look for the logos in the list of recordings.
However, I have always liked the idea of channel logos on an EPG, and the channel logos as implemented on the 922--nice and big and clear and in HD, looks like I would really like that experience. I think Dish is finally able to use channel logos because, if I'm not mistaken, the 922 uses the Sling Guide.