Developers use grey because they think it's the less offensive to the eye (in fact the opposite is true) and by being conservative they will appeal to the broadest range of purchasers.
If not for the red curtains this would likely look very bland.
A bit off topic, but also on topic condo schmooze:
Condo--or another tall building--to block the south view from here? I heard 545 King Street West (Cool Hand Luc location--could explain recent eviction although Ice Cream in the winter is a dubious biz model), and possibly 555 King Street West (denied by Perfect Leather employees) was bought by Hullmark. PL employees said it was Freed and sold for $14 million, but my twitter source says Hullmark, and will remain office use (perhaps longer term will redevelop as office tower to compete with Allied Reit project down the street?)
The influx of new buildings along King from Bathurst to Charlotte all incorporate the use of grey brick and/or spandrel. It is creating a rather gloomy effect on the streetscape. Red brick and an alternative choice of window cladding system would have provided a more warm and welcoming street presence.
Ya, I am just waiting for Freed to tell the City that the SilverPlate Building is too far gone for rehabilitation. What I worry about is that Freed is going to go cheap on the rehab. This work will make or break this project for me.