Ragnar,
The issue here is two fold.
1. You set up the review and your wording indicates that you have a bias toward the photon and against the Halcyon. That's fine, it's your review and you're more than welcome to share your opinion. However, those folks who own Halcyon gear, and are happy with it, are probably not going to agree with your review and are likely going to express that opinion. Frankly, I could care less. I have a Scout xenon and it's been just fine for me on cave exits. I also have had other backups that have been just fine.
2. The more difficult issue, is your commentary about signaling in a cave. Your comments make it clear that you do not have cave training, nor do you understand light signaling in that environment. So trying to tell cave divers what they need, or what is going to work, is probably not going to work out very well for you. Yes, brighter backups are nicer for cave exits. However, burn time, light pattern, and overall reliability are FAR more important factors. Thus, cave divers who've already invested in lights which they feel meet their needs are probably not going to be hugely interested in your comparison of lights that are "built" and not purchased.
For my own needs, I am shopping for another backup light. That light will likely be a Photon, a Light Monkey, or a Halcyon. I've been on all three webpages. As was the case 5+ years ago, the PT page is a mess. In fact, it doesn't look like it has been updated in several years. I can find no relevant information about the current product. It may well be the best backup light available, but the "face of the company" leads to a very poor impression. It's two primary competitors offer a much better presentation, both are very close geographically to me, and I have the utmost confidence in both of their products.
I'm sure you put a great deal of effort into your review. And I am sure that some people will find it useful. But frankly, I'd wager that most people are far more interested in a comparison of off-the-shelf Scout LED vs current Photon vs current Light Monkey. Because personally, I am not going to gerry rig up a backup light to go caving with. I am going to buy a product I believe in, test it, and then go diving.
Best of luck.