Im not a cheerleader for the F-35, but the F-15 is reaching its end of life (50yo design, nearly 45 years in service). They have had at least two crashes due to structural failure.
30 April 2002 : F-15C-27-MC, 80-0022
2 November 2007 : F-15C-28-MC, 80-0034
Both lost due to structural failure.
One structural failure was because of a manufacturing error, not a design flaw that would lead to a failure.