I won’t go into specifics, but I will say I had mostly good experiences. Not necessarily meaningful, I mean good as in “not bad”. The issue with using substances, be they plant or synthesized chemical, is that you might have some kind of life-altering experience, maybe similar to an NDE in that it shakes you out of yourself and forces you to reevaluate your life and priorities. You hear a lot of talk about “love” becoming a guiding force for individuals who’ve travelled those paths. The problem lies in the lack of foundation. It is well and good to pay lip service to love, however without moral theology or philosophy as reigns love can do more harm than good. For example, many of my old friends in those circles see nothing wrong with pre-marital sex, abortion and contraception, and other such social hot topics. They often don’t understand the true dignity of the human person as a Catholic would, and because of that they will ultimately fail to act well on their new experience, despite any good intentions. While the experience may push a person to realize they haven’t been charitable or kind or maybe even decent, it rarely does anything to convict them that their actions here, in this life, will have consequences in the next. In other words, they may well come to see they’ve behaved poorly, but to call it “sin” would not cross the mind. Similarly, they may have a strong emotional response which leads them to pursue some form of spirituality, but ask them about a personal prayer life and it’s a far cry from that of a devout Catholic, or Muslim or Jew for that matter. It’s the spiritual equivalent of having your cake and eating it, too; all of the good feelings one would expect from coming to know God with little or none of the sacrifice and work it actually demands.
By God’s grace I made it back to the Church after all of that, and I would not be the person or even the Catholic I am today without those years of wandering, however I believe it’s best avoided in favor of something substantial and “systematic”. The Church says we are made for Heaven then she shows us how to get there. And you can’t get much better than that!