Paypal - echeque payment - Is it safe?

Just leave it a week to clear first, its coming from there bank and not the paypal balance so you should be ok.

Yeah as the others said, and echeque is still a valid payment, it's just not complete until it clears and paypal releases the money to your account. They'll send you a notice when that's done and only then should you do you part to deliver the goods.

I've even had it used on one of my auto activate products, and the script worked fine. Just kept the transaction on hold and then released it when paypal sent the final confirmation back to my site 4 or 5 days later.

As far as chargebacks or anything, it isn't any different that any other paypal transaction. After the transaction is completed, if they go back to paypal and file a dispute it will be just the same as had they done a direct pay method. Your risk is about the same, as long as you don't deliver the goods before the echeque clears.