I was once engaged to someone who went to quite a famous boarding school from a very young age, as did his sister. Neither of them was unhappy. His father worked in Hong Kong. They went out to Hong Kong every holiday if his parents were not visiting the UK, or for shorter holidays stayed with their grandparents. Many of his friends did exactly the same and he had lots of friends he had known most of his life. I never heard any of them complaining about their school life, mainly they had lots of stories about things they got up to,
His life was a lot more stable than mine, where I changed schools every three years - more, really, as we went back to my grandparents in between postings and we had to attend schools there for about 6 months before moving to the new posting. I have no life long friends like he had, my oldest two friends are from my teens when we moved back to Wales. Education was a bit of an issue, my syllabus changed with every school, and teaching methods were different. It had it's bonuses though - it made me very independent and quite resilient, I'm not scared of change and have had friends of every hue and culture all my life. Boarding was never an option for us.