About the experience with these fans....
I installed one on my '98 Roadking because I pulled a trailer fairly often.
The vibration of the motor caused the fan mounts to break twice. A redesigned mount was issued, but you couldn't buy it separate from the whple fan. My dealer managed to get me one somehow, due to the problems I had had with the fan. (Nothing like a fan breaking loose going down the interstate). I began to carry zip ties to re-attach the darn thing.
Effective. Yes, the engine temperature was noticeably cooler, especially in slow traffic conditions, however, at 40,000 miles I still spun a bearing and had to replace the motor. I might have had to anyway, and I think a cooler engine lasts longer, but its hard to tell if they are worth the money based on my experience. I have not installed one on my last four bikes and doubt I will on any others, for what its worth.