Finally got to see this movie yesterday. It was constantly sold out in theaters near me. I went in with no expectations and never watched a trailer.
TLDR: It was ok, almost a little boring and predictable.
First, like a lot of you guys have already mentioned, the humor feels very forced, doesn't seem fluid or natural. The movie reminded me of how awesome Michael Keaton's batman was then by the time it got to Val Kilmer and especially George Clooney, the world of "batman" changed that it became more of a comedy skit with occasional plot drama rather than plot with bits of comedy sprinkled in. If Marvel Studios continues down this path, I might not even bother watching whatever comes next unfortunately.
Second, sword fighting and hand to hand combat between semi-gods (is that a word) or group of very advanced beings looks great cinematographically, but it's revealed that 2 "primitive" automatic rifles are far superior at cutting down trained warrior veterans who have conquered entire worlds in their past. Really? Why not just use "primitive" weapons in the first place instead of swinging a stupid sword or a stick. Just doesn't make sense. I mean, imagine if you had Valkyrie's ship with her super people-killing-guns at Assguard and could wipe out the undead army in a few seconds flat. Probably wipe out Hela too while they're at it. The movie is just horrible at showing scales of power.
Third, everything was a CGI fest. Not that CGI is bad in of itself but my god, they might as well have Avatar'd this movie. Nothing looked real or believable, at a few points in the movie, I though I was watching a Lego movie. I don't really see a good solution to this. Maybe CGI tech will advance even further but until then, I think they really need use it more conservatively.
Overall, it was just ok. Not sure why it got such great reviews and why it was sold out around here.