My one and only experiance with mops was awful

Each group is different so be sure you find out what your specific group does.
It was very mainstream and shallow. a bunch of upper middle class moms (it was clear I was way below their income level) eating snacks and doing crafts and talking about the general stuff you find in free parenting magazines. nothing of substance and nothing life changing. It was highly stuctured so not even a lot of time to socialize. it was expensive. $120 a year (which at the time was insane for me but I got a scholarship so everyone) to cover child care and craft supplies and it seemed like we still had to help in nursery every now and then. i do not believe children were welcome. at all. Now I don't mind dropping baby in the nursery for a couple of hours of child free bliss. but I like the freedom to choose, especially for infants. and if I am paying for it I want my two hours of childfree bliss. I do not want to be helping in the nursery.
however I know there are free ones and ones that are way more relaxed with kids and not as structured.