I think that if the family home is (almost) always a happy home and the parental support is strong and extensive and there is more than one child (so they always have someone close to their ages) then it's less hard on the children.
But I moved around a lot! I hated it in the end! I was very sociable and loved being surrounded by friends, but it got to a point near the end of my childhood that I stopped making good friends because I was afraid I'd just have to leave them again. As soon as I found happiness I was uprooted again. It was not so hard when it was done all on the same continent, but adjusting to a whole new culture is definately tough.
Most of my family are now in the states and some are in the U.K.. I never feel that I can be 100% me, because half of my personality is understood by the Brits and half by the Americans... Wherever I am I get asked where I'm from because of my accent and I don't really have an answer for them. I have a child of my own now and I've promised myself that I will stay exactly where I am at least until she's finished school.
However, it does give them a bigger understanding of the world, makes them more open minded, more interesting, stronger and much more independent.
This is only my opinion though. As the saying goes; 'home is where the heart is'. As long as your heart and your children's hearts move with you, it shouldn't be too bad. It just takes a strong family with lots of love between them. If the parents' relationship falls apart or the family does for another reason, that's when it all goes horribly wrong.