It seems the PCI devices all have the antenna attached to the rear plate of
the PCI card which seems a terrible place for an antenna interference,
blockage and breakage wise.  The USB adapter type which generally looks like
a jump drive usually includes a cable so you can place the unit to improve
reception/transmission probably have a less effective antenna.

Does anyone have experience using both that could provide insight which is
better and why?

-- 
"The liberties of a people never were, nor ever will be, secure, when the
transactions of their rulers may be concealed from them."

Patrick Henry quote