What is better for graduate studies in computer science, the USA or the UK?
It really all depends upon what you intend to do subsequent to your graduate studies program.
My answer would be to look at the companies and careers at you want to pursue beyond your actual degree and see where they are based and located
Everything that Matthew Lai has said is broadly correct. so consider your future career and then have a look at what the university institutions have to often you in the various places
Apologies for any issues and grammar spelling or punctuation. I’m using DragonDictate