My reasoning being SoF's higher health protects it better against the sneak attacker, and keeps its tank heal ability last the longest.

Under 'normal' rule sets that would make sense, but under no abilities, you're better off with the higher health/ lower damage nearer the front.

I actually find high mana earth decisions quite tough because usually the earth elemental with the self-heal is an obvious choice at the back, but when you get to 30 mana, it seems a waste to have spare left over!

I missed out on spirit of the forest, now it's way too pricey! However I find snipe (as with sneak) is quite weak unless you double it up, which people don't usually do with earth.

Great game, it keeps me thinking! I also enjoy the trading aspect that comes with it too... I'm always on the market looking for undervalued cards.