DISCLAIMER: many on this board live by the creed that love can be sudden and gone as quickly. It's not my intent to say what ANYONE ELSE should live by for their life. ONLY to address what is negative FOR ME PERSONALLY.
My general experience is negative.
As in-people proclaim to be poly-but they are actually out to put as many sexual notches on their belts as possible.
I (quite literally) know well over 30 people who I met all separately-who have ALL SLEPT TOGETHER in the "poly community". Almost all of the "relationships" were under 1 month.
I find this to be much more fitting of "swinging" or "play" relationships and useless to me as I'm not interested in this type of dynamic.
I know 2 other families who actually have long term families with 3 or more adult partners (not necessarily triads). ALL of the others are just rotating through the list of potential sex partners.
"Love As Thou Wilt"