should I buy this 5600 xt red devil or 5700 asrock oc?

Either one will give a good value. This one is supposed to have really good cooling and overclockability. If you want to flash the bios to a 5700 xt, go with the other one.

dos I come with bios update?

newer cards come with the bios update. only the first generation of cards had the old bios. unless the box has a February/March date code on it, it has the new bios.