Apparently there are different varieties of oregano that grow in Greece. The one we both bought as plants have a reddish tinge on the leaves and mine is doing nicely, but spreading out low to the ground more than growing up on thin stalks the way my other oregano grows. Maybe the stuff you started from seeds is another Greek type. You won't find out how you like it until it is in the ground for awhile. My regular oregano is all flowered out and finished growing. The new one is still dark in color and spreading. It started out being about 3" in diameter and now is at least six. I have no idea how much to water it. It is the dry season here so when I water the other herbs I give it a shot and it seems to be happy.
I agree with you, that I won't know until the oregano plants grow big, how I will like the taste of them or if they will be different. I hope your new Oregano plant turns out to be different and you will like it.
I just water my Oregano along with my other plants and they also seem happy with just watering when they need it.