I have some 35 aff programs I work with, it is too time consuming to go all over the place, and I keep them all updated as best I can.
I guess it depends, too, on what type of site you run – a directory obviously has a lot more places to cover.
I am not so much interested in newsletters that just chat, I like getting new promos including the banners and codes. All I need to do is forward the mail and the new promo is up within the day.
It’s just a huge time saver that way, and it also gives the program an advantage because they will always be fresh…