I don't have much experience with other modern headlights but I currently use a Busch & Meuller IXON IQ . It runs on 4 AA NiMH rechargeable or alkaline batteries. It is very bright and has a great beam pattern, cut off at the top to not blind oncoming drivers (like modern auto headlight). The beam is brighter at the top so you get a nice even light pattern from up close to far away and doesn't "waste" light by creating an overly wide pattern.
It has 2 settings, the normal setting is fine for up to 12 mph +/- and the high setting is good for fast descents. Battery life is good, I have used it for 5+ hours on the road using both settings as needed and then for 4+ hours on low as a general camp flashlight without running it out. ( I use 2700 mAh NiMH AA batteries).
* requires optional cable
- Uses standard size AA batteries
- Can run from generator * (hub or sidewall)
- Can CHARGE AA batteries for use in your other devices while running on hub*
- Easily removed for use as flashlight
- Reliable, have dropped mine a few times , and in heavy rain without issue
- Slightly pricey for my budget at around $ 110 USD + $25 for charge/generator cable
- No other real downside points come to mind
If you are researching lights, you probably already know that you can spend an enormous amount of money on a lighting system if you so desire. I found this one to be at an acceptable price point for me and my situation, and have been very happy with it. Hope you find one that works for you...