I've been buying and selling on eBay for years now, and have used paypal in the great majority of my transactions. Although I have had the usual problems of customs delays or inaccurate item descriptions, these things are par for the course in any kind of business.
I do sell and buy items from overseas, but I do a very careful feedback check of the buyer/seller, and the people whom they have bought and sold from. From the type of merchandise being purchased, and the length of activity, I can usually sort out the genuine seller from the bad.
Anyone who sells overseas has to be aware of Italian customs, any buy I have from Italy will get a disclaimer from me saying that I will not be responsible for delays caused by customs. If they agree to the terms, I will ship the item, if not, then I won't. The Philippines is another place which often sees customs delays, the last item I sent there took 6 weeks to clear customs.
Another reason I sell overseas is that on some items I can get a much better price from an overseas bidder compared to those in the US.
Now I happen to live overseas, and I am often disappointed when I find an item on eBay which I like, but which a seller will ship to the "lower 48 only". That I might have paid 1/3 more for his item than an American buyer probably never crossed his mind.
I don't buy Chinese-made products when I can help it, but I haven't had any problems dealing with Chinese eBay sellers. I have always found their descriptions to be accurate, and their shipping quick. In one case, an item I ordered from China never arrived, but the seller refunded my money quickly, and with no fuss.
There is a risk whenever you buy something. I've bought items face-to-face, only to find that the item I bought was stolen. I've bought things that seemed in good condition when I picked them up, only to find that they were moused together, and stopped working as soon as I got them home. "Let the buyer (or seller) beware", as they say.