I've used a 24 site clone machine and have had 100% success with it over the course of many runs. I keep waiting for the one that doesn't root, but they all do, usually within 6-8 days. My old method was cut the clone, dip in hormone, plant in prewetted soil, then onto a heat mat and under the clone dome. I would say I had roughly 80% success with that method. Having done both now, I prefer the clone machine. Cost $70 on Amazon.