I like the Bose SoundDock (a friend of mine has one and the Sound is just amazing), however I haven't really listened to the iPod Hi-Fi. I only put my hands on it for a couple of minutes at the nearest CompUSA. It's a nice looking unit though. The Hi-Fi seems more portable and rugged compared to the SoundDock.
If I had to choose right now I would go for the iPod Hi-Fi.