One major downside: if Fossil has file move detection, I didn't find it.
i couldn't find it on the website, so i downloaded it and it does appear to support renaming files.
jcs@smug:~/Downloads% ./fossil help mv
Usage: ./fossil mv|rename OLDNAME NEWNAME
or: ./fossil mv|rename OLDNAME... DIR
Move or rename one or more files within the tree
Yes, that's an explicit move. That's what I mean by informing the VCS that you renamed a file. It amounts to holding the VCS's hand and means that even trivial code rearrangements require considerable extra care, or explicit support for that precise VCS type from the IDE. Git and Mercurial autodetect moves, so you can freely use any regular tools you want to manipulate your files (command shell, Windows Explorer, Finder, IDE), and "git add -A" or "hg addremove" will properly record your changes.
i couldn't find it on the website, so i downloaded it and it does appear to support renaming files.