The ticket reports for specific Milestones of a project are great for communicating to customers where you are on a project. I also love that I can customize the ticket reports any way needed for the best communication to each individual customer.

We use git and wiki, along with code review tools on assembla.

Tasks are easy to create and assign. Time is easy to track. Assembla is a less frustrating tool to work with compared to similar products. I've recommended Assembla for small teams of 2 people, to larger teams upward of 20. I'm sure it scales well for even bigger teams. There are many tools that connect well together, like referencing tickets in your messages. It makes it easy to organize the entire space.