Everyone has an opinion on this obviously, but I cant wait to move away from my grey screen. Blacks look better on a grey screen, but colors and whites are dulled out to some degree depending on the screen. The FH is the best I have personally seen as far as a grey screen with the least dulling of whites and colors, but it still has this affect compared to a white screen. You dont get something for nothing. You do get better blacks, but at the expense of duller whites and colors to some degree depending on screen brand.
The downside with a white screen is you need complete light control including dark surfaces to get the most out of it, and if you cant do this, then the grey is the better choice. However if you do have great light control, including dark walls, ceiling, etc...White is the better choice IMO. I have a cave of a room and realize now, especially moving to the new JVC which has excellent black levels that a grey screen is not the prefered screen in a situation like this. I look forward to proper whites and colors that pop the way they should.