qtop is a nifty command-line tool for monitoring cluster queuing systems, mainly PBS & torque.
It tries to fit as much information as possible in a screen's real estate,
by joining together the output of commands: pbsnodes -a, qstat & qstat -q.

Output is divided in 3 sections, reporting: a) SUMMARY b) NODES c) ACCOUNTS
Each user gets mapped to a unique letter, according to the number of jobs in qstat.
Symbol 0 is always the user w. most R+Q+other jobs, 1 is next in # of jobs, etc.

qtop suppresses color mode automatically, when needed, eg. try: watch -d qtop
Very large sites should try qtop|less -RS and navigate around with arrow keys.
It is very configurable, and you can either modify command line, variables or qtop.conf;
try qtop -h and take it from there.