I quite like Paypal.

I often use it as Paypal accepts Amex when a merchant may not. Works well and I've never had an issue.

I don't either. On the other hand, it's more of a known quantity than one of these startups.

Curious, why? I could understand it as merchant, but as customer, PP has great customer protection (including partial chargebacks, free return shipping, etc.)

They’re notorious for freezing peoples accounts for no reason or recourse and generally being terrible to deal with.

I wouldn’t call it notorious. I have almost never heard of non-merchants being fucked over by them. And for customers, they are the opposite, super easy to deal with because, like Amazon, they decide in favor of the customer when in doubt.