PvE vs PvP heirlooms

Hi,
I was wondering today and thinkin about heirlooms. The differences between PvP ones from WG and PvE ones from Dala.
My question is, are the PvP ones more viable and better investment than the PvE ones when you twink? I mean, does the resilience actually matter at that amount, does it scale with level as in 2 PvP heirlooms at lvl 19 would give the same amount of PvP damage reduction as 2 PvP items on a lvl 80? Or are you better off taking PvE ones for the crit since I've seen that those small amount at low levels actually give quite a boost at low levels.
Thanks in advance boys.

Resil scales exponentially, the more you already have the more valuable it is.

At 19/39 it's not valuable at all, becomes valuable at 60 if you want to stack resil, and then it's only effective at 78/79 after that.

tl;dr

PvE = better general investment
PvP = for certain specific builds/characters

Thanks for replying, very helpful.