Look at it this way:
Do you want little to no barking, but can never bet let off leash outside of a fence?
or...
Do you want
a TON of barking, but can be let off leash.
There are other differences, but I think that's the biggest lifestyle one. You should probably just get one of each.
They play well together. The collie can get into things and the borzoi will hold down your furniture.