Despite the snark, You've made my point for me! It's not just theory - we've all seen the result of the dreaded "clench," when client grab at the base instead of laying the hand flat. Good lamps are designed to force the proper hand placement for their bulb placement. You can see that in good lamps, both UV and LED. The CND lamp is designed for proper hand placement. Can clients still get it wrong? Of course, but the ergonomic design makes it less likely. I don't want to get into yet another lamp debate, I think CND has not handled the lamp issue properly from the start. And most of the salons I work with no longer use CND, to some extent because of the lamp issue. But the science of how lamps work on gel polish is real and documented.
The difference in the CND Shellac formula is one of its distinguishing features and is likely one of the issues in going LED. Doug Schoon, Jan Arnold, and Jim McConnell all discussed this back in the early days of CND Shellac. And numerous articles in Nails Magazine have covered this topic. The issue here isn't the lamp, its the hypoallergenic claim (lots of people who can't wear other gel polishes can wear Shellac). And (unlike CND) I am not saying that other lamps can't cure CND Shellac - I am saying that you simply can't tell. That's the science, not marketing hype.
Again, I am not defending or advocating for CND. I feel that they have been overly proprietary in insisting on their own lamp. But, given that there is no mechanism for determining a proper cure (and the legal liabilities that come with that), I grudgingly understand their insistence on using their lamp.Clearly, this debacle with their lamps is a disgrace that will undermine the confidence of those nail professionals who stuck with them. I don't know what CND is thinking in insisting on their own lamp and then not being 110% certain of their quality. But all of that doesn't change the science of UV nail coatings.
Good doesn't equal expensive, but if you can't afford a $120 lamp (in the US), or any other requirement, to stay in compliance with your insurance and manufacturer's instructions and certification, you need to take another look at your business plan.