- Worth it is purely subjective. I will spend anything, if I think I need it. Not because I am flush, but because I have been around enough to know what I want, and how long I will have it for. But dynos spook me a little. I think I could buy Phil hubs with some hope they would "see me through". But dynos, and what we hook them to, and the alternatives, are moving too fast for me to commit at this time. We could have solar paint, or just increases in the efficiency of any of the stuff we are running. Solar, computing, and LEDs, are examples of areas with exponential change. Dynos, magnets, and batteries, are areas that are moving fast. But it's just money.
- Dynos are one of those areas where the advice comes from Moonie like true believers to some extent. So you will get X pages of glorious affirmation, which is just what you need if you have already made up your mind. But if you are still undecided, for every person with a Son hub, outside of Germany, there are 100 people who made it through their whole tour with a pair of double AAs. They are just not into Dynos enough to come to this party.
- My experience with lights is that I don't use them much touring. I use clip on strobes for the rainy days, and I use battery lights up front. I do a lot of night cycling when in the city, but found in the boonies, at night, no amount of light I was likely to use would be enough to both ride, and find my way at intersections. If you are at all worried about getting lost, you don't want to be navigating by bike light. People miss turns, and landmarks in the daylight. Commuting, yeah, makes lots of sense, though even there, there are proponents of just going to a larger battery. When going light, I have used the clip on Cateye as my camp light also. You are picking up a lot of cost, and weight, to get a dyno system, you can't even use around camp.
- Nav wise, if you are really worried about getting lost, you need more than electronics, and if you have that stuff, for 99% of bike touring, you can find your way without the GPS. But almost everyone wants electronics, if the chargers were cheap enough it would be attractive, but there are some trips where you are on the same Hwy for like 7000KM, so you know...
- If you are mildly electronically inclined, there are lots of instructables for the bits that go between the dyno, and the device.