My favourite is the temple one. It looks like what you'd imagine Protoss temples to look like, but still manages to look unique.
The mountains also look really good, but I don't think that there's a lot to say about them.
I love the positioning of those egg clusters in the zerg one, really creative!
But otherwise I can't really make out a lot on this pic.
Ok, ironically the toss city this thread is named after is where I have my problems: Combining the different protoss themes (temple, ship, etc.) worked in the temple terrain I mentioned earlier, but here it doesn't quite fit together. If I had to change something, I would probably remove the stone doodads and stick more to the golden colour scheme. Maybe replace the large protoss building with a few smaller ones that are a little more spread out. Add a few of those flying lanterns from the ark shuttle tileset - they look really good in jungle environments, trust me 😀.
I hope I didn't come out to negative, cause overall this is some top-notch terraining that makes me eager to do something myself.