Easytune is ok and in saying that it is just "okay". It is better sure if you know how to and want to go through the trouble of researching how to do it properly, but many dont have the time or the will or the knowledge to do it right. Good on Gigabyte to make an application to make it easy, but if you do have the knowledge or patience to do it yourself, you will virtually always come out with a better overclock if you tweak it yourself.
ya, you can try the 3 presets, and if that is all you want, and they work and are stable, then you are gold. If however you are not stable, then I would go to the bios, reset it and start from there. Overall the tool seems to have conservative settings and the memory voltages may be lower than what is necessary.