Allright, I played one game with full SAGS so far, and it works pretty well.
Creating the map works good and is fun. There are minor strategic decisions one has to make and if you place your tiles well, you get for example the opportunity to place a non-card-door on the entrance of a Salamite-High-Security facility.
What I experienced so far is, you have to cope with your missions. In my sessions, my missions seemed partly easy, partly impossible to resolve. I had to capture the professor, secure the Zombie Serum (the parts i didnt know how to do), kill as many Salamites as possible and shut down the generator.
The Salamite had to generate Spy Points and to find the Laptop and the US Constitution. Furthermore he had to apply the Deadly Virus.
I guess, the missions in which you have to find items can be pretty tough. At least he didnt find any of them.
On the other hand, I was pretty lucky, because the Professor found the Zombie Serum and kept it. So I catched him and everything was done.
But what I can feel is the multitude of possibilities. I look forward to different item-combos, like using Gasmasks and Poison and the like.