Saw it on Saturday, thought it was much better than the first one, which I liked but have always thought was seriously overhyped. Drax is still the MVP for me and Bautista's laugh is just magic, but I thought Quill, Gamora, and Nebula were all stronger characters here than in the first movie (and in Quill's case, less obnoxious). I already liked Yondu but he damn near steals the show this time around. Ego and Mantis were great additions to the cast, and I'm glad that Kurt Russell's turn as a villain was better served than most Marvel villains are. Sean Gunn's character was oddly affecting. Yondu's death was super affecting!
The humor can be hit or miss, but I feel like the ratio here was no different than the first movie, with the hits being a little funnier. Also, the production design was fantastic. The first movie looked cheap-ish at times; in this one, everything from the sets to the makeup and costumes to the creature and planet designs were a huge improvement.
I do agree that Baby Groot feels a little too manufactured (though I laughed at Gamora having to say "Hi!" to him in the middle of the opening fight), and Rocket went from lovable asshole in the first movie to just an asshole -- which, while it may be part of the plot, doesn't make him any less obnoxious. But otherwise, I felt like this movie was much more interesting than the first one and an overall improvement.