Ms skydrive
Not defending apple because if nothing else i am a bit annoyed i cannot put any file i like in icloud.
But i did try both google and microsofts recent efforts, (and dropbox and sugar sync and tonido) and both google and microsofts efforts for me at least simply did not work. Microsoft was crippling slow, 100kb download. Googles in a perminant state of confusion as to what needed syncing.
Dropbox is best but a tenner a month. I cannot afford that. Tonido did not work and so far sugarsync has been fine.
But i really wish icloud was more tha it is. Athough i have to say my contacts, diary etc has touch wood be perfect.