window grids, mullions, muntins, whatever
I have always lived in houses with removable window grids. When I have been in other homes I never really noticed a difference between the permanent and removable. But, then again, I don't do a careful inspection of windows when I am in other people's homes.
Anyway, I have been pricing windows and most salespeople seem to be surprised when I ask for removable. I like them because they help with window cleaning but now wonder if they are considered cheap looking or inferior.