Polyamory emotionally destroyed me last year and left me with serious trust issues when nobody had told me there were others in the relationship until a while in. I have bad jealousy issues, get really attached, and just need to be in a regular couple.
In my opinion, that's just cheating. If your partner isn't open about their other partners from the beginning, and doesn't give you a chance to decide if you want to carry on or not, then they've just cheated on you behind your back. And you're well in your rights to be upset and angry at that.
I don't think I could be in a polyamorous relationship. I can't see myself loving two people to the same extent, and it would also hurt me to know that my partner doesn't love me to a similar extent that I love them. I would get jealous, basically.
So for me, I would want to end up in a monogamous relationship.
I don't have an issue with the polyamorous though, as long as they are open and truthful to all their partners. I can't stand cheating, and I would be devastated if someone cheated on me.