I wouldn't recommend buy Auctiva shipinsurance. The chances of reimbursement are rather small.
eBay requires paying the buyer almost immediately after a loss or damage claim
If you don't agree to pay the buyer, you lose a refund of the final value fee and PayPal fees and eBay freezes your PayPal account. One must wait 45 days before you can file a claim with Auctiva's shipsurance, then besides presenting evidence of loss, you must get the buyer to sign an affidavit swearing he didn't get the package.
It is difficult at the least to get someone to do this a month and a half after they received a refund. The affidavit is worded to scare the former buyer, with notices about fraud and jail time etc. If they don't sign the affidavit, and return it, you are not going to get paid by the insurance company. The chances are rather small that one can get this kind of cooperation, especially if they are in another country. Even then they can still deny the claim.
Two experiences with Auctiva insurance:
In case one, the buyer wouldn't respond at all to my emails requesting the affidavit. Then one day I received a regular mail envelope with the signed affidavit. The insurance company said that the signature wasn't that of the buyer, because they had other affidavits with a different signature. Note that one of the requirements is that you must be a handwriting expert.
In the second experience, which involved lost registered mail, I got the buyer to sign the affidavit before I was forced to refund his money, but Auctiva shipinsurance rejected this affidavit because it was signed too soon, that is before the end of the 45 day waiting period (I strung the buyer out for a month). This buyer refuses to sign another affidavit, he's long gotten his refund and lives in another country.
If you like having a false sense of security, and love aggravation, certainly buy Auctiva's insurance. It's quite a wild ride.