We moved countries when DS1 was 2, and DS2 was 8 months, we then moved countries again one year later, there have been definite affects, some positive, some negative.
On the positive side we are very 'bonded' as a family, I feel that I am showing them lots of real life skills - how to establish a support network for example.
On the negative side they both miss family and friends, more than I imagined they would, and DS2 in particular gets very upset if anyone leaves.
I have huge anxieties about how this will affect them, and try to minimise the potential effects. I talk to them lots about what is going on, we have loads of pictures on the walls of family, friends, places etc. We try to stick to our routines etc etc.
Funny things affect them, I remember with the first move Ds1 being very upset about leaving our car and going in another car.
Hope this helps, good luck with your move. x