I think they both are really good. I ended up with Blez
(by a tiiny margin) because of the hard work of details in the mountains.
When it comes to environmental decoration both participants are more or less equal. My personal opinion is that Blez is mixing a bit too much between heat and cold. A frozen waterfall, just beside some green grass puffs.
But considering the flowing river which supports the soil from going completely frozen, it is possible in a real scenario to have green plants grow up from snow, at least early in the winter. But again the frozen waterfall spot interfere with this theory.
GhostX seem to be more closer to the winter or in an overall colder environment. However using fire on ice pillars and brown mushrooms are interfering factors here.
Nonetheless, both mappers did an amasing job here. Congratz to both.