I used the scheme as I went to buy the car outright for cash, but was offered the PCP, which made sense as I was able to keep my cash in the bank earning interest whilst borrowing money from Fiat at 0% - simples!
I think that the reason there are so many 500 owners using PCP's is that effectively this has been Fiats method of discounting the 500 via finance deals and not cash discounts on list price. This has been good for all 500 owners as it has helped maintain strong residuals, however outright cash buyers are effectively subsidising the low rate finance deals. The Panda on the other hand has always been available with good cash discounts for outright purchase and is less expensive generally too.