PP is one of the most common way to transfer money, also it is easy. What I don't personally like about PP are refunds. Because PP terms&policy defend buyers to much which means that you can lose money which is really great for scammers on the other side.
If you look on ebay there are people who say that they didn't received item/ that they received it in bad condition or w/e, which is not the case and ofc PP will in 80% cases refund a person - so you lose money.
Another thing is while trading for virtual goods for example, it is really easy to get refund and as a seller you need to cover all things that you did the trade properlly.
Furthermore scammers even say sometimes that their PP was hacked (buyer ordered something from you for like 500$). so they receive an item/good and receive money back because their PP was 'hacked' - I mean sometimes this really happens and this is why it's not that simple to be one of the most secure companies in transfering money.
What I like about PP are small fees, fast transfer of money, you can call them at anytime for their support - yes we need to wait few days to windroaw out money to card it but still.