This is a review of Invincible, season 1, the Amazon Prime cartoon, and Invincible, the comic, the entire run.
This is actually the second comic I've read all the way through, with Scott Pilgrim being the first (apart from very short things, like Unflattening or Red Son). I don't know how much I would have enjoyed it, if I hadn't watched the show. I heard J.K. Simons' voice when I read Omniman's dialogue all the way through, and so on; I think this helped attach me to the characters more.
I think part of it is that I usually get attached to characters by getting to know their thoughts, through their words; but comics are inherently, verbally, a pretty terse format. The visual characterization is meant to fill in for the lack of words, but it isn't something that I'm used it.
The TV show was fun. Cartoons are inherently campy, but this one embraced the campyness in a way I wished The Boys did. I read on Reddit that Invincible (the comic) was made by someone who basically loves comics, while The Boys (the comic) was made by someone who thinks comics are dumb and used up. That definitely shows, I think, in the way that The Boys likes to spit on comic tropes, while Invincible likes to play with them.
Or, to look at content: in Invincible some people actually want to do the right thing, in some sense. In The Boys, pretty much no one does; or the best one's motive can become is revenge or trying to stay alive. It just isn't as fun to watch.