Been playing around with the Hound beta. So far, the only thing it really has over Google Now/Voice Search is being able to combine multiple things in one query. (e.g. Show me Asian restaurants that don't serve sushi; What is the population of Japan, Germany, and France?) This seems kinda limited though. A lot of the multi-tiered stuff I asked just gave me search results. (Bing, in case you're wondering. Search, images, videos.)
Both allow you to search using context, though Hound is a little bit better in some situations.
Google understands my voice quite a bit better than Hound and make less mistakes.
Both are very fast. There were a few times Hound came out faster, but the difference is quite negligible overall. Hound is nowhere near as fast as that video, for me.
Hound has a bit of personality like Siri and Cortana, but it's just as useless here as it is on those.
Hound has some built in games, which happens to be my favorite thing about it so far. It has blackjack, hangman, and guess my number. They're pretty good time wasters.
All in all, I'm impressed. I didn't expect a company like SoundHound to put out something this well. It does quite a lot of what Google Now is capable of except the predictive stuff. As far as I can tell, you can only ask it questions and tell it to do stuff (send texts, make calls, navigate somewhere, etc.), but there's nothing that gives you relevant info at the right time. Still, good first outing. It's just not enough to pull me away from Google Now.