I checked with my colleagues. I work in an office with 50 people, all using TC.
These are the must have features that seem to prevail:
- folder sync, à la beyond compare
- key mappings for shortcut commands
- total layout customization
- automatic recognition and mount of zipped like files. In general, automatic recognition of text/binary files
The core editing features are the most appreciated ones, and that's where TC is hard-nosed.
For example no one uses ftp/ssh etc, there's plenty of tools for that.