Like around 2011 to 2015? Before it became available on major exchanges?
I used LBC to buy bitcoins when there is no enforced KYC requirements to trade there and it was most reliable at that time because most exchanges didn't have fiat deposit for many countries after that 2017 lot of local exchanges popped up so we can get better deals for fiat than LBC in the recent times.
I used LocalBitcoins for my first purchased Bitcoins too. In fact, everyone should create good trading relationships from the P2P marketplaces. One day, you won’t be needing the platform to trade with one another. It would be a simple peer to peer transfer, preferably in person.
Good trading history and trading with someone who is actively trading should be important when we trade on p2p because people sometimes go for the higher price offer and end up getting receive money from hacked bank account which is one of the issues when we are trading with p2p.