I'm currently in the same situation trying to decide between these two. I've personally seen both of these in stores, Sharp at Best Buy Magnolia store and the Vizio at Costco. But I haven't seen them in the same store side by side to make a direct comparison that's why I'm still on the fence about it.
At the BB Store where I saw the Sharp, the sales person there popped in a blue ray disc of Iron Man 2 for me to see the picture quality. He wasn't trying to push very hard to sell this model but from looking at the picture the black levels on the Sharp is excellent in my opinion. If you've seen the movie, the scene where Iron Man was flying around in the expo, the Sharp almost made it look 3D. The picture and color overall I think looks great on the Sharp and 60" is a big plus. The only thing holding me back from getting this now is just that it is only a LCD rather LED and it seems the LCD will be phased out by LED in the near future. But to be honest, I personally don't find the LED TVs are that much better than plain old LCD TVs in terms of picture quality.
At the Costco store where I saw the Vizio, I wasn't able to get to see the tv with a blue ray movie and the demo loop that they show in costco is not very impressive. The Vizio was actually the one that I started looking at first because it has the latest technology and loads of features so I really wanted it impress me when I went to see it but after seeing at Costco I walked away un-impressed. However, its not a fair comparison since I didnt get to see it in blue ray. I'm trying to find a store where I can at least see the Vizio in its full capability before I make the decision to go with the Sharp. But at the moment, I'm leaning towards the Sharp and very tempted to just get it because of the larger screen size.