I liked the movie, the music and chorepgraphy were good, Emma Stone is just awesome in anything she does, and Dennis Leary and Martin Sheen were cool.
However, I could see no reason why they needed to reboot, even if re-casting was necessary. The story bought nothing new to the franchise - at least nothing new that could not have easily been tacked onto the outstanding franchise (Gwen and Curt Connors were already established as characters. If Peter and Mary Jane had stayed split up at the end of 3, they could have used Venom and Lizard in 4, working up to Hobgoblin and Gwen's death in 5).
While I agree that Spider-Man 3 mis-stepped by being too obvious in its approach and tacking Venom on the end when he should have been the main villain in Spider-man 4, I thought 1 & 2 were pretty much note-perfect in terms of Maguire's character.
They tried too hard not to go over the same ground in this movie so it ended up being too humourless (although kudos to Stan Lee for one of his best cameos), and Peter was barely a nerd. Most of the dialogue was quite leaden and, while Garfield's performance was creditable, it just lacked what makes Peter Peter. Sally Field was given nothing to give May any sort of presence either.
In fact my overall opinion was that these were the characters in name only. There was nothing on screen that identified them as the characters from the comics. Like it or loathe it, the first trilogy did a fantastic job of portraying characters that were recognisable - especially JJJ!