I never quit buying my comics every week, but a year or more ago I mostly stopped reading them. I've been catching up, so this week I read GGPR from about #2 on and the MMPR from the same time. Leading up and going through not just Shattered Grid, but the first Drakkon arc too.
When GGPR started, I had the distinct impression that it was just another take on the Power Rangers, so I sort of ignored the hints that it was actually the same universe just earlier. I didn't see most of the first season of Power Rangers, so I assumed that Matt and Billy's internship were references to the show, not things that were connecting these. Since I "knew" it, I resisted it until it because a cool revelation late in Shattered Glass.
I agree the ending was kinda weird. I think a year from now we will compare it a lot to Avengers.