The Full Metal Panic manga was actually quite light compared to Sigma... To be honest Sigma is a bit too serious when compared to its initial chapters.
Story:9
Basically revovles around the protection of Chidori, though Sigma focuses on less school and more of actual war. The story is pretty interesting though from time to time it gets pretty confusing and at times even disturbing.
It is confusing for some parts as there were quite a number of unexplained situations and some things are very technical. For the disturbing parts, there were quite a number of plot twists that really stray away from the more light-hearted storyline of its previous arc.
Art: 7
Not much to say about this, character designs and actions are pretty consistent but during intense battles the art can be so confusing due to the fighting being blur.
Enjoyment: 9
For a mecha series this is pretty good.
Overall: 8
Storyline and slapstick comedy could be better balanced to give this series a likeable view instead of being so dark.