As someone who dislikes eBay and prefer to deal with companies, rather then individuals, the UKs preference for eBay is interesting. Working for an eCommerce site we noticed that customers would prefer to deal with a lady in Scotland over us, for certain types of products. She just posted our product on eBay, added a few £ to the price, ordered them from us, typed in her customers address in the shipping fields.

Worked out for everyone, given that her customers would rather order on eBay and pay a little extra, compared to dealing with us. We got the price we wanted, plus we didn't have to deal with customer service.

It's weird, one would expect eBay to be more of a wild west than Amazon marketplace, but in my experience the eBay sellers are fast and mostly trustworthy.

That's because on Ebay, there's seller feedback, and it's actually useful. People leave negative feedback if there's a problem, and the feedback is specific to that seller. If a seller has been on there for 20 years with a perfect 100% feedback score, you know they're trustworthy, and if they've been on there for 1 week with 0 feedback, you know they're not.

Amazon comingles listings from Amazon themselves, FBA, and independent sellers shipping things themselves, so there's not really a good way of telling if you'll have a good experience or not.