There definitely is a drop in initial productivity, after the exploratory phase is over there is a hick-up in the output because I'm writing test cases. Then, as soon as that is done there is a huge boost in productivity because it becomes much (and I can't emphasize enough how much that really is) easier.
So it is more a matter of uneven output than an overall loss, overall it is definitely a net gain. Hard to quantify though because you will never know how much time you would have spent debugging and testing if you had not written those tests first.
It is more of a feeling than that it is measurably slower, in fact it is measurably faster but when writing the test cases it feels slower. I hope that clears it up, sorry for the confusion!
As for fewer customer visible bugs: yes, absolutely, no doubt about that.
So it is more a matter of uneven output than an overall loss, overall it is definitely a net gain. Hard to quantify though because you will never know how much time you would have spent debugging and testing if you had not written those tests first.
It is more of a feeling than that it is measurably slower, in fact it is measurably faster but when writing the test cases it feels slower. I hope that clears it up, sorry for the confusion!
As for fewer customer visible bugs: yes, absolutely, no doubt about that.