I'll tl;dr this for you guys.
The Expanse starts out as a very high-drama, Clancyesque political intrigue in a fairly hard science not-to-distant future, but in space.
The are three major factions (Earth, Mars, and Belters) and are all pretty gray.
Earth is working to maintain its dominance in Human society, Mars - politically independent but still dependent on earth for food, air and water - is looking to sever its dependence on earth, and caught in the middle at the Belters, miners who are exploited and mistreated by both sides. But not for simple moustache twirling reasons; both Earth and Mars are dependent on the output from the mines to keep from imploding.
Any GoT comparisons fall apart because there are straight bad guys in the form of a shadowy corporate conglomerate who somehow managed to develop technology that vastly exceeds that of either the planetary governments in complete secret, but you can mostly let that slide until the This "harder science fiction" all gets tossed out the fucking window as they find Alien star gate technology and various SJW talking points get more words.
Shocking Ending: John Wu is a fucking moron with shit taste.