I'm currently on volume II of Clay Blair's discussion of the U-boat war (which, aside from being rather defensive about America and Canada, and pretty scathing about the Brits, is excellent) and it seems for the first 3-4 years of the war the Germans were reading all convoy and a lot of naval traffic without great fanfare.
It seems that the British theoretical and American technological innovations are given more weight, is this just a case of history being written by the winners?
Blair himself doesn't seem to go into too much detail, I assume because of the breadth of his scope.
I have answered similar questions here, here, and here. The B-dienst managed to, while the RN and Merchant Navy were using book codes, decode a similar proportion of messages as Allied codebreakers were reading German messages. However, the RN's book codes were considerably simpler and easier to break than Enigma; the Allied achievement was certainly more impressive. The Germans were very poor at disguising the source of their intelligence, so when both the Allies and Germans were reading each others messages at the same time, it was very easy for the Allies to recognise their codes had been broken, and to switch to cipher systems the Germans never broke. The Allies were a lot more careful, and the Germans never really recognised their vulnerability.