We had to plant boundary screening when we moved into our house, garden is 12m x12m.
We already have a magnificent pear tree which is about 40 foot and goes straight up!
We ruled out bamboo, invasive and not the right look for our garden.
We planted:
2 small laurels. These have grown SO fast. Evergreen. We like them and manage them aggressively to stop them getting too large.
2 red robins. Beautiful and great value. Have also grown quickly. We prune at leas twice a year. Drop a lot of leaves but easy to gather up.
Trellis with pyracantha. Nice habitat, takes a while to get going.
1 rowan. Beautiful, taken a few years to get going. Think it will be gorgeous in ten years but has a very open habit, deciduous, not brilliant screening.
1 Cherry. Again, gorgeous.
1 hawthorn. Great screening in summer, nice habitat.
My conclusion is, laurel and red robin are cheap effective but needs you to maintain it a few times a year - it is not heavy work.
We removed birch and leylandii when we moved into our property as they had consumed our garden.