nfs(and sd). but to not ignore your question: the best thing for productive would be to have it on ubi/emmc that would be a dream come true. but for getting the peaces together i prefer the nfs for i can do most things on the pc(compiling) and can test how they work out on the phone. otherwise something crashes and you have a destroyed filesystem(for good!). and further as long as it is not working i want to keep maemo sane.