Each market has pros and cons IMHO.
I don't do Facebook, just because I don't like Facebook. Nothing to do with cues or cue sales.
I watch Ebay constantly, and I watch here. I watch Craigslist, Buya, Goodwill and others.
It costs nothing to list here, as well as numerous other markets.
Ebay provides numerous tools, as well as protections for buyers and sellers. I don't want to argue those pros and cons so I'll just say those protections exist. It's a "real" marketplace so if you are generating revenue beyond a threshold, it's going to be reported to the IRS. Some people don't like that.
Ebay also reaches a very large market.
A lot of stuff on Ebay is overpriced, but there are still bargains to be had.
I mostly buy, I don't sell much. When I do sell it is most frequently among people I know, often from here, but also locally. And when I sell or trade I am not generally trying to suck the most value out of a cue, it's mostly a friendly thing and I will pass on a good value to a friend.
Each market is what it is, I don't let it bother me.