...
the best benefit is probably just getting treated a tad bit better by the staff...my impression is that employees, almost without exception, will go a bit further to help a diamond when the flyer needs assistance.
also... getting the last upgrade seat on a fully packed flight after an SDC is pretty cool too...but I'm sure that pisses off a lot of plats.
if Delta would just get their IT/Award Calendar/SWU programs fixed... they would have one hell of an airline.... but until then....
doug