OP, May I suggest that you visit the Peter White website www.peterwhitecycles.com to get the info that you may require. It seemed to me to be pretty unbiased, as he sells battery and dynamo operated lights. He has done quite a bit of evaluation on this subject.

LBS don't carry dynamos most of the time because they are expensive, and lets face it, if it's going to just sit there, the LBS needs to move it and a cheaper battery powered light will move faster always. Whether it is better or not is up for you to decide not a bunch of obviously biased bike riders. Ford or Chevy? They'll both get to to where you gotta go, who makes the better truck?

So, now I will weigh in to my preference. On my new bike, I wanted a dynamo, so I went with a SON28 on a new 36 hole rim. A luxos U headlamp, and a toplight brake plus tail light. However, I wanted charging capabilities and this has it, and that's another subject. On my tandem, and mountain bike, I use a flashlight mounted to the handlebars for the rare instance I/we get caught in the dark. I have enuf to think about on a daily basis, without having to remember to take my light or battery pack off to charge it tonight, so I went with a dynamo-its always ready for the task. Both have advantages and disadvantages. It's up to you to decide what will work best in your application.

You have asked for opinions here. Remember, opinions are like butt holes. We all got 'em, and they all stink!

Also FWIW, I have no attachment to PWC, its a resource for me too. Also, I drive a Toyota Sequoia, and a Kubota Tractor!
Cheers