I cannot have butter. Sub cold Earth Balance? Coconut oil? veg. shortening?

I haven't had a chance to play with it myself, but a reader wrote to say he'd tried it by replacing 80% of the butter with coconut oil and that it was a little tough, but flaky. Another reader told me she had good success with Earth Balance baking sticks, and based on their descriptions, I feel like that must be the better option.