with the repeaters, if they get bad signal, all they can repeat is the bad signal
plus, you loose a lot of bandwidth, since the repeater is having to talk to your main router, and your device at the same time.
Take a look at powerline networking, it will put the connection from your main router to the repeater on your house power wires, leaving the repeater full access to it's wi-fi hardware for sending the new network.
You can even get all in one powerline boxes with wifi built in.