<p>I think Katia is the best, since she gets a 20% markup just like traders, but since it seems like an exploit to clear out most of Franco's inventory in a few trades every time he shows up, I don't use her.
</p><p>I am liking Marin, who gets a discount of 1 in 5 items for building and upgrading, and crafting at metal workshop. Marin makes it easier to have Improved stove / workshop / metal workshop, 2 rat traps, a rainwater collector and lots of tools by day 6.
</p>