I just got back from watching Ant-Man and the Wasp. Here's some of my thoughts on it...
I really liked Evangeline Lilly as the Wasp. She was great in every scene she was in.
I didn't feel like there was any real villains in this film. Sonny Burch (Walton Goggins) felt like a small-time villain at most.
I thought I was going to find Michael Peña's character in the film irritating, but I didn't and I thought he was used properly.
I wish Michelle Pfeiffer was in the film more, I felt she was underused. Maybe they're saving her for Ant-Man 3, if that happens.
Other than the tie-in during the mid-credits scene, this film felt pretty stand-alone.
Like most of the reviews in this thread, it was okay, and very low-stakes at best. I don't know if it's better than the first Ant-Man film though.