My Cordons (see here, here and here for how I planted them) are looking good this year. They've already put on quite a bit of growth and many have apples on so I'm quite please for their second year.
They haven't taken much work to look after, so far, weeding around them takes a bit of time (I've been mulching with straw as well which helps) but you only have to prune them once, in the summer, and thin the fruit if they crop to heavy.
The other job is to tie them back in. I just use string to tie them in so that it rots away and doesn't strangle the trees as they grow. These means that I have to tie them back in to the bamboo canes every year. It doesn't take long, even with 27 trees, and gives me a good opportunity to make sure each tree is doing alright.
Anyone else have cordon fruit trees growing?