It's actively hostile to buyers.
Like, try to find a "kinda nice" bicycle. You can't find the bicycle category (though it does exist as a sub-group of Sporting Goods), you can't just say "show me bikes" unless you hack the URL, you can search for the word "bicycle" but for some reason people selling a "Specialized Rockhopper" think you know it's a bicycle so don't use that word.
Oh, and when selling, they just suggest random categories instead of letting you choose from their heirarchy. So you get bicycles in Hobbies. You get them in Sporting Goods. You get them in Bicycles. But... You can't search for them by type.
That's not even complaining about the lack of attributes, like "type=BMX" or "type=Mountain" or "Size=Large" or "Frame Material=Carbon Fiber"... all of which are in Craigslist and eBay.
And! when searching, they actively work to inject ebay-like selling (non-local) into the mix by resetting my distance preferences every time I change the search. "Find bicycles" -> "Find bicycles in 30 miles" -> "Find 'Specialized Rockhopper'" -> Why am I getting "Ships To You" results?! Why am I getting non-bicycle results?! Oh. They reset my distance again.
^-- BTW they do this because they actually make money when the sale happens through FB. If you just buy it in-person with cash they don't get a cut. Misaligned incentives, as they say.
And! even if I do find the bicycle category, if narrow the category by searching with a word in there, like "Rockhopper" it takes me out of the bicycle category to do the search!
G. A. R. B. A. G. E.