It seems like forever since Apple gave any love to its media device. In fact its only(!) three years since this 'hobby' device last saw a significant update. In that time new competitors have arrived and proven the market, we've been subjected to ridiculous rumors about actual Apple Televisions and Microsoft has added heaps of media and TV consumption capabilities to the Xbox.
So the new Apple TV has a big hole to fill in Apple's line-up. There's no question than There's no question that it does this, and in doing so will drive millions of upgrades from existing owners.
However, the introduction of Siri and an app store don't suggest a compelling reason for those who passed over the earlier and cheaper version to go out and buy one now.
The truth is that unless you buy into the iTunes experience for all of your music and video purchases its not especially interesting. Unlike the Xbox One that can pass through and control your existing TV service, with the same voice control and search capabilities (if you have a Kinect anyway) the Apple TV still ties into Apple services or partners only.
As more partners come online Apple TV (and perhaps Apple's TV subscription service) will be more attractive. But in my eyes, unless you're bought into the Apple content network aready, there's little reason to do so now.