Greenlee made outstanding chisels at a time of high quality in both steel making and chisel making in the USA.
Those would be as good as or even better than the Stanley 750 series, and up there with makers like Union, Buck and Peck Stowe and Wilcox; and there isn't that much difference between them and the highly desirable Thomas Witherby and James Swan chisels.
You will like them I think.
MC