In reversible method no escrow can help you because after transaction escrow will in danger if you reverse the payment. Since you're still not yet a trusted member so if you want to exchange than you need to use non-reversible method to buy bitcoins.
Yes, exactly when trading with paypal we have to see if the sender of money is trusted or not and while with bitcoins even if the guy is new if he is sending us money means the funds are clear and no reverse can be done. So, escrow is possible. I think that's the reason why so many people pay 15-20% fees to get BTC for their paypal.