Biggest reason being, in mt4 I get 100% of the profits, at the low level account you share 40% of your profits with them. and every month they take out the profits to pay you and them, your account goes back to your funded level.
I think the5ers had resoved that part. They pay for the profits while they let your account grow for the next milestone to increase your funded capital. They also do not charge monthly subscription - only one time enrollment fee for being evaluated.