I loved the 39 steps, absolutely thrilling read from the beginning to the end. The things is, given that it was written, what...? 60 years ago? It reads very much like a contemporary thriller in terms of structure and pacing, and yet of course, it obviously has the language and values of a different era.
I have tried reading other Buchan stuff like Prestor John, b-u-u-u-t, one finds ones self nashing teeth at some of the language and cringing at some prett un-pc values. But then, you know, you have to consider when it was written. In a similar way that accusations of rascism by Tolkein (orks being black, good guys being aryan/blond etc) is too easy a shot, I'd hesitate to level the same sort of thing at Buchan.