Yeah I'm overall quite impressed with the GG GURPS book.
I feel like there's a bit of a tone mismatch between the drama-heavy comics and the simulation/detail-heavy combat rules. But nothing you can't paper over with some work.
It also means the different parts of the rules have very different feels. The Weird Science and Spark-stuff rules are very light on details and open-ended. Which, again, suits the source material pretty well.