The recommended order for the Tokyo Ghoul manga is to begin with Volume 1. Sequentially moving through each volume will give you a seamless and immersive reading journey. It'll allow you to grasp all the nuances and details of the story as intended by the author.
It depends on personal preferences. Some people might think Tokyo Ghoul is better for its original story and character development. Others might prefer Tokyo Ghoul:Re for its continuation and new plot twists.
Tokyo Ghoul manga is quite lengthy. It has a lot of content to explore. The specific length depends on how you count the chapters and volumes. But it's enough to keep you engaged for a while.