I have Green Giant I love. They are supposed to get big though... I can believe ten feet.

We have a Green Giant planted in full sun next to our driveway in a smallish space. They are very fast growing, which I love. So it doesn't encroach on our driveway space, I prune back the branches on that side every spring and summer. It will probably look funny in the long term as the other sides I'll let grow naturally and it may look lopsided, but I don't want to give up the privacy it provides.

They'll shoot up one to two feet per year, if not more.

I have Nigra(Dark Green) & Green Giant Arborvitae planted at the back of our yard for privacy, in shade to part shade. The Green Giants are growing quicker than Nigra, but seems to want more sun - they appear to be thinning alot, but still healthy. The Nigra's handle the shade better and stay denser.
I had Brabant Arborvitea growing in this area but moved them last summer into more sun. These stay thinner, have a narrow top & are inclined to a single leader - so need to plant them much closer together than Nigra & Green Giant to provide any privacy. But they grow in height very fast - much faster than the others & handled the shade very well. I moved them only because I didn't buy enough to plant tight together, and couldn't find more at the stores in following years when I realized my mistake. Plus the shape of each tree is so consistent and symetrical, I thought they looked better w/ plenty of spacing between them. Crowding together seemed like a waste.

If you have deer NO arborvitae!