What are the real problems with k-2 and other sister "fragrances?"?

I know all this stuff about people smoking K-2 and it getting them really high off a little for a shorter period of time than weed. But then again i also hear all this crap about how its really bad for you. I havent seen any firsthand problems with it and have friends who smoke it with no problems but i want to know are there any real problems with it? I DONT WANT GOVERNMENT FUNDED RESEARCHED I WANT UNBIASED RESEARCH! Also, i know there are other kinds of fragrance out there that keep changing the recipe and making it more and more potent as the govt slowly follows behind and illegalizes each one. Problem is the govt is always 1 step behind. I know 7H is the new recipe thats now legal and if it gets made illegal wont another one just come out? What are all the other kinds of fragrance that can get you high?