I don't have a problem with PayPal putting a temporary hold (delay) on new funds coming into an account (as long as it's clear what the guidelines are for such a policy), but what I do have a problem with is PayPal freezing an entire account, including funds that are more than a year old. Which PayPal absolutely does in some circumstances.

5-year ex-paypal customer (and hated being one the whole time). 6-month stripe customer (and happy every minute of it so far)