This is an excellent jumping on point for anyone that wants to catch up on the first twenty years of X-Men, The first issue of this graphic novel consists of explaining the history of the team including most major battles. The next few issues explore the new X-Team members and their relationships with each other.
Fans of the 90's animated X-Men cartoon will be expecting something a little different than what they get out of this story. Kitty Pride was hugely popular after Dark Phoenix and it is no surprise that the writers wanted to capitalize off of that popularity. Not all of the stories are Kitty centric, but most of them are, including Days Future Past.
The titular story is very good and very dark. It was a place that marvel went to pretty often in this time period. You get to see the graves of the biggest heroes in the marvel universe, and then you get to see some x-men breath their last. It is obvious that they hadn't explored Wolverines powers or back story all that much as they have him aged consistently with the rest of the team in the future. It is a well told story and a foray into sentinels and time travel that would be repeated for years to come.
The final story is all Kitty all the time. We get to see her use everything she has been learning in the Xavier School in order to attempt to fight off a monster. It is a Hanukkah story that should be brought out every year.
When they titled this collection they were going for the most recognized name and the story that still resonates with fans. Most of the collection are the writers finding their way with the new team and without the leadership of Scott for the first time. Their is a new dynamic and it hinders the storyline somewhat as you generally get individual tales that doesn't advance the story. Because Days Future Past occurs in a possible future, the writers did not feel bound and were able to open up in a way that really tells a great story and implies how close the team is to become.
If you are an X-Men fan, this is a must read if you haven't already. If you have never read the X-Men, this is a great place to hop on and start running with the new team (well, the first new team). This was a comics code authority title and should be acceptable for anyone old enough to read it.