Great question! These kits allow you to test up to 10 products for about $50. You know I'm a great fan of safe products, so my first instinct is to say yes, get it. I like these kits because they give me information quickly and at home. Getting something tested at a lab is very expensive, and a homecrafter like me isn't going to spend that kind of money on one small batch of lotion, so these kits seem to be the best fit for the job.
As an aside, I cannot tell you how much I want this mini incubator! And I have found this kit at Lotioncrafter, for my American readers. I haven't found them in the European or Australian retailers yet, and I encourage links in the comments if you have information. And please note that I mention these retailers and create those links as information, not as promotion of a specific company or product.