I'm using git for dev with c2, and it's been an bumpy experience.
Biggest problem is here as a bug report, and is main cause for never-ending conflicts:
project-file-contains-ui-state_t105824
I don't mind so much the conflicts, but it's rather difficult to resolve them beacuse a single change in editor can change the projcet code on multiple places. Proper diff tool designed for c2 would be of great help, i'm currently using kdiff3 and it's not intended to use with C2-like projects and sometimes it's rather difficult to solve conflicts.
Except team communication who's doing what, and separating all logic on multiple event sheets (and including them as necessary) so devs don't step on each others toes i have not found a good solution, but it's manageable (sort of). I tend to create the whole project structure with all of the event sheets created but empty, and hope for the best.
There's also a tutorial from ashley on working with svn and is a good source of info, but does not touch the conflict problem. https://www.scirra.com/tutorials/537/ho ... svn/page-1
Unfortunately, this is my main problem with c2, makes working in teams rather difficult, and i do believe it will be hard ( if not impossible ) to fix. Fix would probably need to change the .xml files structure (and subsequently change some code in the editor, and ashley already stated it's hard to change editor code). It makes me kinda sad.