I tried to sync for several years and it never worked. I tried everything. Eventually we just moved to using one computer and sharing it. Its not healthy to spend all the time on it anyway. Having a pooled machine has a number of social benefits as well.

So we have a single laptop, three smartphones (my oldest daughter has one as well) and they're all handed in weekly to me for data extraction and archival.

The laptop is a Lenovo X201 so it can go anywhere and we have a docking station and full desktop setup if you need anything a little more healthy to use.