Check out my full and detailed review at Sticky Bunton, found here. But for the TL;DR version:

SIGMATA has a lot going for it. It easily captures the feel of 80's dystopian cyberpunk with an alternate history America. The book also is rather timely, as it ties in events occurring around the world, and protrays them in an easier-to-digest and educational matter that the author has proven in his other work, Cryptomancer.

Mechanically speaking, SIGMATA is easy to pick up and teach, and is light with physical requirements (5d6 and 5d10). The game system is built for newbies as well as for the experienced player.

I also felt the game has one of the most balanced super powered mechanics out there while still keeping things interesting.

Sadly, the game does have a few flaws. The art is nice, but there isn't enough of it in my opinion. The core mechanic is simple, but it can leave more to be desired by some play groups due to the limited actions (but they do remove the issue of decision paralysis). Combat of any sort can be a bit one-sided with a heavy-handed GM due to how the game is designed, which is a concern for most of the groups I've shared this with.

Overall, it's a nice game that's a clear improvement over Cryptomancer, but suffers some of the same flaws.

If you like cyberpunk, 80's vibes and technology, and a game that is both quick to pick up and an educational tool, then you should absolutely give SIGMATA a glance.