The bigger the screen, the more lumens you need.
So, screen size and gain, what content you watch mostly (sports, gaming, movies?), ambient light, etc.
Then there is personal taste. Do you prefer your movies to look like they do in a commercial theater? Or like on a tv/plasma (very bright)??
The W7000 is gonna be brighter for sure, but it's contrast and blacks will also be way worse vs the HD250. An issue for movies, but not so much for sports.