Is that even in a controlled lighting type scene?
Technically yes, but then you can say that about a black screen too!
Today, it seems to be that grey screens are unnecessary in dedicated theaters, because projectors have started to really push the contrast envelope already, and that's even at affordable prices.
Grey screens are the least interesting to me, personally, by far. Not that there aren't excellent grey screens out there ($$$$), but for me, I'm simply not interested.
Look towards your room conditions and PJ choice firstly. These will assure you of maximizing contrast.
The only times I ever consider grey for others is when the PJ in question is a business class PJ. No shortage of lumen output, but sorry contrast ratio. The thing is that if this person ever upgrades to a high contrast HT projector, the grey screen is rendered nearly useless, IMO.