Atrix HD - never saw it, cause Motorola leaved South Korean market.
Nexus 4 is kinda cheaper version of Optimus G.
One X - HTC leaved SKorean market either, but One X is an old model, so dont think they can be compared.
One S - saw it, one guy bought it in USA - its small, like S2 and thats a mid-end phone.
In my opinion Optimus G > S3 > Nexus 4 > One S > One X