morrison1984: A3 only needs 3k (well, 4k, but you get 1k for free) to reach Silver. However, with your travel pattern, you can easily reach *G there (19k) in a short time. If you want a higher chance to upgrades, it's always suggested to participate in your main flying carrier's program. (See below)

Given Premium Economy is still a bit of a niche product, I'm not so sure on which routes it's existing. As usually Asian carriers over a better product then European one's, I would check out about TK's premium economy product, which is (from what I've seen and heard) more like a business class/economy class combo, but still priced at (more expensive, but affordable) economy prices. Also, their program is quite good to achieve *G, and if you would choose them as the main carrier, it would of course be better to have *G on them than on A3 or any other program. Their *G lounge in IST is also what can be called industry leading standard. I think if Premium Economy from IST to Asia is available on those routes you'll be taking, together with their superior lounge in IST, and their good food in the air (Already quite good in plain economy, much better in Comfort Class - their Y+ product) plus rather good earning rates when flying, would probably make them my choice.

That said, also the Y+ product from TG is good. I don't have experience with the Y+ from ANA, but it might be worth to have a look at it.

Both TK and TG offer quite a lot of connections to China/Korea/Islands around there.

Besides that, I'm not perfectly sure which would be your perfect program/carrier, as Y+ is always a bit hard to choose from, but just from the hard and soft product, I would go with TK, and if you indeed do so, also choose their FFP to put your miles to.

Happy flying ^