When some of the features of dynamic dataset expansion first came out (may
have been the master dataset and perhaps some combination with other
features like jumbos) there were problems.  Are there still problems? Should
I avoid dynamic dataset expansion?

Just upgraded our Orbit backup software so we can use the option which
allows us to keep the system up during the entire backup.  Ran into some
messages when the database logging was turned off during the backup.  The
Orbit folks told us that it is best to keep logging turned on.  Okay, but we
need to increase the capacity sometimes . . . so thus my need to use dynamic
dataset expansion.