eBay has some newer product-focused pages and features, but they don't create the kind of problems you see on Amazon.
It also seems somewhat harder to keep creating new seller accounts on eBay. I've been ripped off several times by highly rated sellers on Amazon that disappeared after a several weeks long case pending against them. Amazon resolved it satisfactorily, but it meant that I would have gotten the item faster from China.
All my personal experience, of course.
Of course ebay listings have multiple products, but not in the same super confusing way you see on Amazon.
"mixed reviews and the unknown of which seller is more likely to ship a good product" - Being unsure of which seller is best also exists on eBay
I don't think Amazon's listings are confusing. You usually have size and color variations, and sometimes things like multi-packs. I guess that is subjective.
Counterfeits: yes of course, just as many if not more
Multiple listings for the same product with different prices: yes, it's by design!
Advertising: not as much, but it is present
Fake reviews: the product reviews on eBay are mostly useless. The only thing you can rely on is the seller reviews