It's less funny than its predecessor, partly because the clerks are a trifle older and more sensible; partly because more of it is a real travelogue describing German customs and personalities. It can't often be as unconsciously revealing¹ as ...Boat was for the English middle classes.
No surprising observations; gentle mockery of the German love for order, with the semi-respectful stipulation that the German character he describes doesn't just expect other citizens to be controlled, but does scrupulously follow the laws himself.
"The German can rule others, and be ruled by others, but he cannot rule himself. The cure would appear to be to train every German for an officer, and then put him under himself....
[Duty] is a fine ideal for any people; but before buckling to it, one would wish to have a clear understanding as to what his 'duty' is."(p. 341)
Just after that, and probably as important to a pre-WWI reader, a comparison of the German and English commercial character: in which he says the Germans are less competitive because their classes are not so fiercely marked; no-one not born into the German aristocracy can get into it, and everyone else is on a standing of more or less bourgeois comfort and mutual respect. By his description, this led to less luxury than English social climbing, but a great deal more independence.
¹ I don't assume that Jerome was unconscious, no.