I use start all the time, but also frequently curse at its stupid argument grammar and its interaction with auto-quoting on auto-completion. For example, type
start C:\Doc
Next, hit tab to get
start "C:\Documents and Settings"
Now, hit return, and watch a new command window open with title "C:\Documents and Settings".
I think xdg-open defers to gnome-open/kde-open/... depending on what DE is currently running. Not sure about that. Anyway, xdg-open should be installed anywhere where any kind of DE is installed.
On Windows the equivalent is start (e.g. start C:\ )