This study1 builds upon the 30-years HCI research of collaborative writing and focuses on users' experience of writing together in today's context. By interviewing 30 participants from both academia and industry, the paper examines how people write together using today's commercially available systems. The analysis focuses on the new co-editing capabilities (e.g., track changes) that are integrated into commercial tools and thus adopted by users widely in the last decade. These capabilities enable new ways of working together (e.g., directly edit the content at the character level at the same time), but users reported reluctance to fully commit to these new working styles. We thus systematically analyze users' rationales of why they do not want to write together while they are writing together with other. We argue that the development of collaborative writing tools is far from finished and these findings provide insights for the design of technology, and suggest future directions for research.