This was by far the best of the three movies IMO. I never enjoyed the previous director's style and lack of special effects. He was not experienced like the current director and it makes a huge difference. Even Halle Berry said in an interview that Singer really held them back in the previous versions and they felt those movies were a little boring because of it.
As a true comics fan and collector of X-Men comics for 25 years, I was incredibly impressed with the merging of the famous storylines from the comics and the drama they created with the characters. This director dropped in many subtle references to other X-Men stories that only true readers would notice. The reviews are extremely mixed, due to the critics' misplaced loyalty to Singer, but I find that a terrible excuse to dismiss this movie. This is an oustanding movie on it's own merits, and the record box-office suggests that most people would agree ($120 million opening weekend & 4th best box-office premiere in history).