I went to an excellent one at my maternity hospital run by the breastfeeding advisor midwives. Becasue of them, we were fortunate always to have LOADS of suopport. They were also very good at getting the mums to talk to each other - especially getting someone who has "got to the other side" of a problem to talk to someone just encountering it. For example, my ds didn't put wieght on, athlough he SEEMED to be feeding plenty. I talked to a mum whose ds wouldn't latch on at all - and she had been prepared to feed him on EBM, until she found out he would feed througha nipple shield. Compared to her, my problems seemed small. Later, I was the one the midwives got people to talk to, to reassure "new" mothers that failing to folow the growth curve is NOT necessarily "failing to thrive"
They would also come around and check people's latches - if you wanted them to - and weigh your babies - again, if you wanted them to. That way you could avoid the baby clinic and the dreaded HVs! Becasue of them, even though ds had an EXTREMELY slow weight gain, I was given the confidence to continue. They did refer to the consultant paediatrician, just in case, but he took one look at this manifestly happy, healthy and alert child, and asked how my dad was (who used to work at the same hospital).
Because of its attachment to the maternity hospital, it meant that if they/you had any concerns, you could get a very quick referral.
It was very simple - just a circle of chairs, with a padded area in the middle for the babies to lie/crawl on. They supplied orange juice and chocolate biscuits - we only found out later that some of this came out of one of the midwives pocket - although later she did get proper funding for it.
They were also able to loan out expressing mchaines, if you were struggling. That's what helped give me the confidence that ds WAS getting enough, as even when he was dwoning loads of EBM, his rate of weight gain didn't change.