In my opinion, I think recruiting ECA's will earn you more.
And it depends how much their products are sold. Each ECA, I think can sell more than four products. This will give you a guarantee of earning. Also, you don't need to attain the rank of EA in case of ECA.
There is no guarantee of PSA because I have only one active PSA and he's just only earning VPs from actions. Not from sales/purchases