Mike, I really like the fender mounting. For one thing, it gives me a large "triangle" of light day and night. I've been told by many people that they really catch attention when I'm moving -- several people in Fort Morgan told me that they wished all motorcycle had something like them, because it was easier for them to both see me and judge my distance and speed.
Some people say that lower mounting of the lights cuts down on the aid they give the rider at night, but since I aimed my headlight correctly, I've been very pleased with the distance that I can see at night. I'd guess that I would see deer at over a quarter a mile away. I can see the highway mileage markers at 7-9/10ths of a mile. Curve markers, highway identification signs and the like show up at a mile or so.
The Denalis have made me comfortable with riding at night. I know the risk factors amp up with wildlife, etc., but I've ridden a lot of miles at night and have pleased with how well I can see. My old Concour had a 130V high beam (which wasn't legal for on-road use, but I never got stopped) and I PIAA driving lights that were 35W each. The NT with it's two 55W bulbs have a better headlight than the Connie did and the 10W Denali LEDs are way better than the 35W halogen PIAAs.
When I mounted the Denalis, I was dubious about their ability to stay aimed correctly when mounted on an unsprung part of the bike. But I've never had to re-aim them except for times when someone has bumped them and knocked them out of whack.
Someone mentioned using Loctite on the mounting bolts and having their fender disintegrate, but that is known result of using Loctite near plastic of many different kinds. So, if you mount them on the fenders, DON'T USE LOCTITE!!