Newsletters are good if you either provide great content that the enduser actually wants or you provide a great product at a great price that the enduser can't refuse. It's all in how you prepare and what you provide in the newsletter. On the opposite side of things I've had a client who sent monthly crappy newsletters. Looking at stats tracking for the newsletter he would never get a single order. Yet, every month he would spend 3-4 hours creating the newsletter. He wouldn't take my advice and great a real promotion or any really good content. It was always, buy my products, here is $1 off a $40 item! Just make sure you have some way of tracking the newsletter to see if it's effective.
Personally, I never has done it. But I'm not going out there on a limb and say it doesn't work. Write good content and I'm sure you'll get a positive response.
It can work if you have a good list, good content or good service/product. I'm generally not a fan of it either but I've got 1 client that it works well for. Do 1 a month for training classes. Last newsletter we sent out a couple weeks ago got 7 people to join the class at $150/person. So it works for them and they do it every month. Some months they don't get anybody but as long as they can show it works a couple times out of the year they continue to do it. So get a good list and then promote a good product or service.