Not from my experience. They would not assist with a seller that would not return an item that didn't fit. Absolutely no use to me.

Not anymore, they have a staff that is primarily liberal and takes a liberal stance on business dealings.

Definitely not. They will steal your money and change policies as they please.

EBay is fairly trustworthy, it's the eBay users that abuse the platform.
EBay is in business to make money and they like to control the way users use the platform.
It's more of a shop and sell at your own risk.