P1 gen 1-3 or gen 4?

I am in the market for a new laptop. I daily an X395, I like it, but I have a few gripes, mainly that it runs out of ram if I look at it wrong, but it could have a bigger battery and a better screen. I just drug my W520 out to address those concerns to make it a bit more comfortable writing code. It barely fits in my bag though and it weighs over 5lb.

I think the best thing to bridge the gap is a P1. It's not a classic, but they're still pretty badass. And I think they're just small enough to fit in my bag.

Thing is, the gens 1-3 are all dandy, but it's hard to find them in the right specs for me. I want no touchscreen and no Nvidia GPU. I did find a couple, a gen 1 for about $250, and a gen 3 for $400.

The gen 4 however has the sick 16:10 screen than guarantees higher quality and no touchscreen, it seems to be easier to find models without hybrid graphics, they have a bigger battery, and a faster and more efficient processor. The only downside is it's a bit taller due to being 16:10, I think it'll fit in my bag ok since it's thinner and only 3mm longer than the w520 without the 9 cell battery. I found one for a little over $600, not cheap, but not bad for what it is.

So what would you do? G1 for $250, G3 for $400, or G4 for $600? Of course, the cheaper models have definitely seen more wear, which is a factor.

Edit: I have heard the scathing reviews of the G4. But I assume those have the GPU, I hope the non vapor chamber cooler works well for just the CPU. I would love to hear your experiences and I'll definitely be checking over the thunderbolt ports and stuff if I go that route.