Got a chance to see this today as well. Some things I liked, some things could have been better. I sort of look at the Spidey movies through rose colored glasses. I got my first Spidey comic when I was 5, basically learned to read with Spidey comics, and have been hooked pretty much ever since. I think Andrew Garfield makes a great Peter Parker/Spidey, and his chemistry with his real-life girl Emma Stone as Gwen is very well done as well. I really liked Dane DeHaan as Harry as well. The Spidey suit in this movie is my favorite of any of them I think, and looks like it came right off the page.
Electro, I wasn't really sold on. Not sure why, just wasn't working for me. The movie seemed to jump around a lot as well, but I think a lot of that was due to future movie/movie universe set up. The Rhino stuff was pretty minimal, but has some potential. I'm glad that had more of a resolution to the whole story involving his parents set up in the first movie. All in all, not perfect but an improvement on the last one I thought. I will admit to having problems completely disliking anything Spidey or Star Wars, and tend to watch a lot of these popcorn movies like a kid would. I'm always just excited to see these heroes on the big screen, whereas it was just Superman (and later Batman) when I was a kid. Pretty good movie though, and I'm curious to see where it heads from here (staying spoiler free as possible). As a side note to those with kids, our daughter (who is a Spidey fan) didn't enjoy it. Thought it needed more action and was "too sad" in parts.
As for an after credits sequence, I had already heard about the clip from X-Men (as part of the deal to get Marc Webb out of his contract with Fox apparently), but others in our audience were like "what the hell?"
Dean DeHaan. His dad is a member of PSWCS. 
He was actually on Fallon this week, and asked if his parents were fans. He talked about his dad having a basement with "floor to ceiling Star Wars and a Princess Leia dartboard", and mentioned that the first thing he wanted to do after finding out his son got the role was to tell his "comic book group". Kind of a neat story.