The thing is, the younger people are doing FB and you pretty much have to list everywhere to have a better chance of selling.
Depends on your age. For the teenagers, FB is for "old" people. Like email. Grandparents LOVE FB because they can see new pictures of their grandkids every week.
Scammers, slimy sellers and freaks infest every free ad listing service. However, at least in my area, FB Marketplace has taken a huge chunk out of CL, leaving mostly the idiots behind (but bringing along plenty of scammers). When I listed the Honda Pilot on both services the first time around, I got one good lead from CL and many from FB. Second time around I didn't waste my time with CL and it sold quickly through FB Marketplace.
FB marketplace is a joke. I've got my Cadillac listed up for $1,400 with photos and ALL the information on the car. All I've gotten are "Will you take $700?" "What's wrong with it?" "Does it run and drive?". I retort to all these messages with "No" or "Read the ad".
If you have a SPECIFIC question, then ask it. Otherwise don't waste my time.
I too can express my dissatisfaction with most responses from both services. I put "Needs transmission work" at the top and bottom of the ad text. Most responses were oblivious to this fact. Instead of hovering over the ad all day, I waited until I got several replies and then responded to all of them at once with copy-and-paste.
Yeah the worst is the lowballers. I didn't even get "Will you take $XXX" it was just "$250" messaged to me (Talking now about a mower I sold). After a while I just ignored these. But no matter how you handle it, someone will find a way to waste your time.
I did get a bit of revenge. On the Pilot, I had an obvious car flipper (FB feed full of cars for sale for the past 2 years) giving me a sob story about how he needed me to deliver this car for him 50 miles away, for a lowball price, because, wife, family, kids, sob stories went on and on. I just egged him one while I sold the car to someone else and then put him on ignore.