I have always stuck up for PayPal when people would complain and say that they limit or hold funds in the accounts. The truth is, paypal was right in many cases, and the horror stories you have heard about were not always very accurate.
PayPal is changing. Are you offering products or services? If products you will likely be safer. If services, or intangible items, you're going to be experiencing some problems within the next 6 months.
Newer accounts are more likely to experience 21 day holds on funds, the same applies for older accounts who don't provide shipping information on products, services will be out of luck.
If you are running an offline business and using paypal as a way to process most of your payments, I would suggest moving to a REAL merchant account ASAP.
One of my paypal accounts, one that made them over $8,000 through transaction fees, was placed on a 21 day hold earlier this week. Spoke with a manager in the Risk Management Department of paypal and he said there was nothing I did wrong, just changing their policies and it will be reevaluated every 35-40 days.
Anyway.. start looking for a merchant processing service, there are many out there that are great. iPayment is a decent one and they include a gateway with authorize.net, would recommend checking them out!