My wife is a beta tester and is running 12-14 hours a day and the techs at the computer stores are stating that the external harddrives are meant for backups only and will not hold up to the constant access.  

Nolan
I don't know why the techs are telling you that but it's simply not true.  I run a 500 Gig external SATA where I run all my Runtimes with both Poser 6 and 7.  It's basically like running an internal HD.  It works great.  The external HD are made to access as well as storage.
Adrian