What a dilemma!

So the auction helped me so much that i managed finally to get a copy of DayZ in my inventory with the profit i made from selling Gems :D

However, here comes the dilemma! I saw on steamtrades the day before yesterday a topic asking for DayZ in exchange of Shroud of the Avatar. Last night i added the OP and we discussed a bit. Below is the dialog:

Me: So, DayZ for Shroud of the Avatar?
Him: no exactly. dayz costs only 27.99 while soa costs 41.99. it isnt fare
Me: So, what do you suggest?
Him: offers. offer me keys and dayz or games and dayz
Me: Hmm, how many keys do you want?
Him: i dont know, offer me :)
Me: And how about the games? Which games would you like in addition to dayz?
Him: offer me :)

The truth is that i have no idea how much exactly a key costs (i believe CS:GO costs 1.84 atm but i have no idea about TF2 as it has so many keys) nor if Shroud of the Avatar is worth the effort (is it really? looks so promising!).

But let's say that i want to trade with him. 7 CS:GO keys plus DayZ are almost 41.99 Euros/Dollars, right?

EDIT: What would you pick? DayZ or Shroud of the Avatar?