Melatonin supplements

I've had chronic insomnia of and on for most of my adult life. I've used Rx sleep aids like Ambien and I've used OTC sleep aids too. They work at helping me sleep but I don't like waking up groggy and hangover-like.   Now that I'm back to TTC I want to use as little of those as possible. 
Trying a semi-natural route with melatonin this time. Anyone ever use these? What was your experience?