This is BS. Feedback on eBay has nothing to do with PayPal payments or any payments period. I have over 540 transactions and I can tell you that. I have dozens of transactions that I never received any feedback from. Some are more conscientious than others in providing feedback. Doesn't mean I didn't get the money! That's just a stupid statement to make.
While you have a lot better feeling about doing business with eBayers with hundreds of positive feedbacks....or 100% positive feedback or close to that. As a previous poster stated...they all have to start somewhere. I suppose this could be a scam but the worst that can happen to you is that he doesn't pay you...you cancel the auction with eBay...you get your seller fees back...and then you relist it. I don't see the point if this is a scam? I guess he's trying to get you to send him the iPhone before you receive payment? Just make sure you do the following:
Once you receive a PayPal payment...transfer the money into your designated account immediately. Usually your bank account. It will then take 2-3 days to post in your bank account. Once the funds appear in your bank account...you have "secured" the funds...it is safe to send the item to your buyer.
One last note. There are what is called "Verified" eBay members. These are people who do link a verified checking or savings accounts to their eBay accounts. Therefore, eBay provides greater fraud protection to the transaction. I like to see verified eBay members but it's not a deal breaker. Number of transactions, percentage of positive transactions, all are indicators of honest people.
I'd move forward with the transaction but just make sure you get the secured funds before you ship the iPhone.
If you have less than 100 feedback and sell an item for over $100(or ANY item ebay/paypal determines to be "high risk for fraud" ie: IPHONES) PAYPAL WILL HOLD YOUR MONEY UNTIL THE BUYER LEAVES POSITIVE FEEDBACK, or until you can prove it was delivered to them. You should research before calling people stupid. I ran into this several times last year selling iphones before I crested 100 feedback.
https://www.paypal.com/cgi-bin/webscr?cmd=xpt/Marketing/securitycenter/sell/SaferPayments-outside