Is the arsenal a viable option??

Might be a dumb question but would it be efficient to make my newly added t13s from stables or from the t12-> 13s from arsenal. Not only arsenal made troops because you have to have some first. But THE QUESTION IS: is it cheaper or more expensive to make troops from arenal. Is it even worth it?? Takes more or less speed ups and is it more Rss then just training them from stables..?