(Disclaimer: This is not a review of the product from launch. This review is as of the current patch and fix on December 22nd, 2014. The game could totally be in a better or worse state after the fact.)
Halo: The Master Chief Collection is nearly exactly what a collection of the Halo series should be, with some minor sacrifices to smaller stuff such as armor customization. When Matchmaking works, the sheer variety and options you have will be sure to keep you entertained for a long time, and the Campaigns are fully playable and as good as ever. The collection is truly a Halo fan's biggest dream come to live.