Hello,
Well, for one thing it really depends on how old you are as when flying Cargo your usually trying to sleep during the Day, which is hard to do. Of course if your younger you can tolerate much more also, like less sleep etc.
Pax flying can be fun if you have good FA's, and have decent layovers of at least 48 hours. International flying with the right company, and seniority affords this luxury. Jet lag and time zone changes are the cons.