Tortoise is reallt simple, you just have to be careful while merging files, if you don't like the tortoise merging system use winmerge.
Testcomplete project and organization files are IMPOSSIBLE to merge, so, if anyone changes them, the rest of the people of the team need to update the file before making any changes.
These are the files (they include script and keyword organization files, project variables and options, etc...):
*.mds
*.tcLS
*.pjs
*.tcCfgExtender
*.tcScript
*.tcKDT
This is my advice to work with TC in a team
1 Project Suite
Several Projects acording to different products or people working in TC
All the helper files imported equally to all the projects as well as testedApps with relative paths and nameMapping file.