Arnoldr,
Remember the Novatac/HDS/Ra are all designed by the same man, with the Novatac being the oldest and Ra being what we presently buy from him, with all the newest perfections applied.
As has been pointed out in this thread, the lights you were looking at are older designs. The state of the art has improved significantly over the last 4 years. Here are some of the improvements:
1) We have returned to constant power regulation. I only did one Clicky design that used constant current regulation. That design had problems with low-end flickering. I left the company that produced that design and based on all of the posts on CPF, I assume the problem was never fixed. HDS Systems is the only company with a constant power regulation design and that design has proven to be very stable and one of the best regulation systems used in any flashlight.
2) Our new armored and padded bezel design fully protects the front of the flashlight. This allowed us to upgrade to using an ultraclear glass lens without fear of breaking the lens. The glass lens eliminates most lens scratching common to plastic lenses. But if you are really hard on a lens, you can get sapphire instead.
3) We now have a smooth battery case interior so your battery will not be damaged when the flashlight is dropped. We also use a unique dampened dual spring contact system that prevents damage to either end of the battery and maintains electrical contact even with severe impacts - without excessive compression forces.
4) We have changed to lightly loaded heavy duty threads. The old design used heavily loaded thin threads that could wear out after a couple hundred battery changes - not my design.
5) We have added a sealed switch with gold plated contacts for higher reliability.
6) We have increased the minimum runtime from 30 minutes to a typical 1.25 hours while providing significantly higher outputs.
7) We have added support for many different output options including IR, 170 lumens, high CRI.
8) We have added fully automatic detection and protection of rechargeable batteries.
9) We have made numerous improvements to the user interface. Both the Option and Brightness menus work the same so there is less to learn.
10) We have removed failure modes that were inherent in the old design. The result is, our lights can take a lot of abuse and keep on working:
11) We are still innovating.
Henry.