I have found that any conifer is problematic planted close enough together to form a screen. They end up rubbing bald spots on each other, and when you lose one, the tree on either side looks like hell.
Plus the growth rates can be slow.
Other options for screening:
Alternate Eastern white cedar with something like columnar birch, or columnar crabapple. (I sell a lot of parkland pillar birch, and emerald spire crab for this.) The birch gives you quick coverage. The cedar gets some winter protection from the birch.
Put in multiple rows. EWC typically is about 4 feet wide by 20 feet tall at maturity. So plant on 6 foot spacing, and put a second row several feet away with the second row allined with the spaces.
For faster results plant two rows of shrub willow. Most willows get ratty looking after a few years. Cut one row down, and let it start again from the root. Do this on a 4 to 6 year cycle
