Hipporemote + XBMC on a Mac mini with the night skin in logo view is MUCH better than anything on the appletv. On the other hand, iTunes store videos will not work with it, Netflix and YouTube plugins are a joke.
Appletv is amazing with Netflix, even with the included remote. YouTube is great, and AirPlay is fabulous.
For local content, XBMC is king, and free. For streaming content, AppleTV wins hands down.
One thing I hate about the apple TV though, is that after a power outage, I have to reset my Apple TV settings, all of them. Irritating as hell.