This is the heart of the matter, the reason the established church is up in arms againsthem. I have incorporated some of these rituals in my worship and my church home is united against it, so is my personal family. I've done a LOT of study and prayer. Here is what I found.
The possible bad, first. If it is used for salvation instead of using Christ, it is a path to death. If it is used as a path to keeping Christ and God a part of every minute of our day to day living, it is a path to more abundant life.
It can be used as a way to judge others. My church is doing that with me. We can't blame the judging on the actions being judged, it is apart from that. If you join a church that celebrates the feasts and you don't want to, you are going to feel left out and they are going to wonder why not join the party. Just like the people judging me in my church, there will be people who sin in that church by judging.
I can't watch people who use these rituals as part of their life because I don't know any, so I got books about it. Almost every life was helped by living this way, it is not a downer in the main but a key to productivity and happiness, but in the same way our church family helps our life. It is Christ and who we are that is the real part of it, we just use the church family to help. If we said we are saved because we go to church it wouldn't be right but that doesn't make going to church wrong. It is the same way with hand washing and prayer when we get up, or any of the rituals.
God says he is going to unite and make Jews and gentiles one. Jews are against it, saying we have a false God, they only know Christ as God tells of Him in the OT. We say all Judaism is a false God in the same way. God is truth.