I finished volume 1. It's a harem series in a high school setting, so expect to see all those tropes that come with that (Tsunderes, dense guy, misunderstandings).
What makes this one a bit interesting is that a lot of it is told from a first person point of view with our dense hero, so we hear what he sees, and since he is dense some of what he sees isn't quite what's going on. Like, one girl looks away when he turns to her and he thinks she is being cold towards him, when she in fact is probably looking away out of embarrassment.
The characters aren't that interesting as of now, and I doubt they'll get much better. Our protagonist Orimura is just stupid and dense (he doesn't see anything sexually; like, one of his childhood friends promised him when she got older and good at cooking she would cook him pork for life... He took this as an opportunity for free food, and not as her offering to be his wife). The supporting cast fit into some tropes, although Orimura sometimes incorrectly reads their characters, so you do kind of have to work to figure out which trope they really are. Houki, the forced lead and cover gal is honestly not that endearing to me, and our protagonist can't even really recall his past with her, which seems like a recipe for disaster. The cast is rounded out by Cecilia (Brit Ojou character), Rin (childhood friend #2) Yamada Maya (teacher) and Chifuyu (Sister and Homeroom Teacher).
The Mecha gets introduced pretty early on, and it's fairly important, though harem shenanigans probably take up more pages. You only learn some small details about the history of its invention (created by Houki's sister, developed for space travel, used in sports, only to be used for emergency military operations). We get a few opportunities to see IS in action, though really only two combat scenarios. There's probably more to learn there.
Overall, it was ok. I think it does some stuff that I find fun (like Orimura's horrible cliche sayings, and his confidence in his very wrong deductions), but yeah, it wastes a lot of time with harem stuff. I think introducing Rin in this volume was a bit much. Her story kind of takes over the plot halfway through the book, whereas the other two gals I didn't think dominated the first half as much. I'd like to learn more about Chifuyu too.