I know Dutch is not out yet but I decided to include him anyways.
But I think T-1 is the best overall piece......
Here is how it works for me.
T2 has the best likeness, but it's the weakest piece overall. Body proportions are all the way wrong out-of-the-box, pose is not iconic at all (it's OK, but it doesn't screams "Terminator" for me). I'm also not a big fan of the bouffant hair (Arnold had this kind of hairstyle in some T2 scenes though).
But when it comes to pure likeness & details - it's a winner.
Conan headsculpt has the weakest likeness from the whole list (still I gotta say that Andy Bergholtz did some absolutely fantastic job on it too) but for me it's the best piece when it comes to the overall character representation. The pose is most iconic you can only imagine (same goes to the moment that was captured), paint apps is pretty impressive on that one too (much better than on T2 PF, which has the weakest paintjob from the whole list, not including Dutch of course) & what's the strongest part is the body sculpt & proportions. It's Arnold-Conan right there. I also love the diorama feeling of the whole statue. Still gotta admit that Arnold itself is a little bit small for 1/4 scale (still nothing criminal, it doesn't look like it's in 1/5 scale or something).
T1 PF has the best paint apps to date, great pose (still, matter of taste, some folks hate the pose), good clothes, very close body proportions & phenomenal headsculpt by Trevor Grove. But then again it is still not as good as T2 headsculpt for me. When I look at T2 headsculpt I have a feeling that he captured even his wrinkles right lol But they are really close + sculpt of the hair is much more impressive on T1. Again, from overall quality/character representation point of view T1 is light years away from T2 (not in favor of T2 of course).
And Dutch is somewhere in the middle. It's great, no doubt, and the paint apps will be improved even more (I guess & I hope lol), but the body sculpt looks a little bit exaggerated, proportions could have been much better & for me it's not as good overall as T1 PF or Conan PF. Still very promising product.
I really don't see a clear winner, as I think they're all quite good.