Well, for the best overall image and lovely, realistic colours and deep, cinematic blacks, then go for the Pioneer 428XD. If you need your pictures to be razor sharp (and have a full HD resolution of 1080p) then you should go for the Sony W3000. However, if you do go for the Sony set, you will miss out on those wonderful sumptious colours that you get with the Pioneer. And, when you actually sit at an appropriate distance from the set, like you will when you have it in your living room, you probably won't be able to tell that the Pioneer's picture isn't quite as sharp. But you will be able to notice how much blacker the Pioneer's blacks are, and how much more cinematic the Pioneer looks.
So, the Pioneer is the better set. However they are both excellent sets, and it is a possibility that you might even prefer the Sony (there's always an element of personal taste when it comes to images on a tv, just like with hi-fi) so you need to see them both for yourself, in the flesh so to speak. Having said that I reckon that you should get both of them.