What is best in life? Crush your enemies, see them driven before you, and to hear the lamentations of their women!
Personally I learn them all. I don't necessarily find any religion better than the rest except for the fact some priests are easier to farm than others- Ie: set/yog/mitra in beginner areas. As far as raiding is concerned, obviously the titans will be weaker than a flying God,and the snake covers more ground quickly. Let's not forget the RP value of all the religions aswell, because sometimes it's just more cool to be Ymir in the north with a castle dedicated to his icy prowess. The power of ambrosia and purified flesh is do good at the start aswell, but as you level there no problem getting aloe pots and some exotic flesh to boost your hp regeneration easily and skip the soul farm.
To touch back from the start, again, no religion is best in my opinion. It's only a matter of time before you get them all.
Or you can just stick with Crom, as a true Atlantean should, and wait for their bigger endowment slider racial update.