As a consumer of cheap blanks; open pored wood will generally end up MUCH darker after finishing than tight grained wood - analgous to end grain (you can test by wetting with alcohol), and (possibly - maybe just my bad luck) have a bigger chance of finding punky areas in the blank.

A non-punky straight grained open-pored blank will have the advantage of being lighter per cu. in. than a tight grained one.