I have bought at least five of Elitech Fixed Frame screens, the screen quality is excellent and the price is fantastic. Elitech screens got 100% positive feedback with more than 1800 reviews on eBay.
As to my knowledge, Elitech is a very strong competitor of Elite screen, both of them sell projector screens made in China, their quality are both good, but Elitech screen's price is much better than Elite screen.
Whether to buy a white one or grey one? That depends on your special situation: if your room is completely dark when you turn off your light, you should buy a grey screen, because the grey screen surface offers you better darkened background, creates a high contrast, sharp and vibrant image. However, if your room has ambient light after you turn off the light, or if your projector's ANSI lumen is less than 1800, you should consider buying a white screen, which gives you a brighter image than grey one.