I fell behind on this show due to real life (y'know how that tends to happen), but I've been catching up this week and I dig it! The series is doing a great job with atmosphere and visual storytelling, the characters are likeable (or highly unlikeable - that Akane is a deplorable psycho), and the monsters are cool, 3D-style issues regardless. The show has a good sense of humor and solid action sequences, with an effective score by Shiro Sagisu. SSS Gridman might not be exceptionally made, but it's very consistent; and if Trigger can keep this up to the end I think they'll have one of their best titles yet.
The guys over at Sakuga Blog are doing a great job - going into the production, the design, etc. Apparently the show is loaded with references to the original Gridman as well as all those Transformers references; I haven't seen the original yet, so I don't tend to catch them (guess I'd better consider that Toku subscription), but it's pretty cool how many details they've snuck in.