I saw far more talk about WHS than I did Time Capsule. Further, the talk about WHS was much more positive than the talk about Time Capsule. I'll concede this is likely due to the circles I'm in and the information sources I read, but in the end I doubt that
there really was much difference between these. Both are niche "devices". Not many home users are really that interested in running a server, even one dedicated to backup (note that WHS does a whole lot more). If they bother with backup at all they either
just use an external drive, or possibly make use of a backup service like Carbonite. In their niche, however, I'm sure both products do very well. WHS is a great system and I know several people who run it.