There's absolutely no way to review this comic without spoiling it. Before I read it, I had it spoiled for me. I really recommend that you read this issue before proceeding with what I think about it. It's actually pretty fortunate that my day job and other pressing matters prevented me from finishing this until a week after it hit shops.
It's been talked about and now it's here. Jonathan Hickman's X-Men has started. House of X #1 hit shops and we start to get a lot of answers to questions we've had. We just don't get all of them. The first issue leaves as many questions as it answers.
One of the comics that came out this week from Marvel was a preview of Jonathan Hickman's House Of X and Powers Of X. While it could be argued that any major shift in direction is technically a reboot, it isn't an entire relaunch, ignoring the history, especially with what led to this point in X-Men history.