I had bad luck with the soft-sided mesh exercise pen - Sadie got her head stuck in the small open area in the bottom - fortunately I was home and heard her yelping!!! I finally bought the following ex-pen and absolutely love it - got the 36" high pen so she can't jump out of it.
http://cgi.ebay.com/ws/eBayISAPI.dll...m=130018500263
Good luck and don't worry about leaving your pup alone while you work - someone has to pay the bills!!