You know, I've heard that about YN. Now, I know they're rather new. I like their approach, I've seen them at Shows. But, you "know" you never really know until you have a very experienced Manicurist tell you the real deal, so many cheap products have so much hype to them....
I would love more feedback, why is it so good and one of the best System? 
Not so new now, I first came across them on here and made a point of finding them at Excel, about 5 years ago, I was very impressed with them, they showed me an amazing silver glitter nail, they put the silver glitter on my pinkie nail, then while it was still soft, pushed some mesh into it and pulled it out, looked like net curtain
then he covered the silver with black and using an efile buffed it back to expose the silver, the black had filled the mesh lines and the end result was a silver nail with a black honeycomb patten through it. I kept that nail on for 4 weeks, no lifting, no discolouration, very impressive. I still buy their drill bits.
At the time I bought a pink and white try me kit. Personally, I didn't get on with it, I had just started using nsi attraction and I found that far easier to get on with.
I think this was because I'd done a 121 coversion training day with nsi so I was absolutly sure of my ratio.
Which brings us back to your origional question, because I am sure I would have got on much better with young nails products if I'd had some training with their products.
Which products are you using in your training course?
I ask because I think every known brand is covered by someone on this site and they will be able to pin point product ratio for you rather then general guide lines which I think is what you are after:hug:
