Sorry to hear of all these troubles. Paypal is not perfect for sure, but I believe it is the preemminent way to cyberbank.
Many of these reported issues are people issues, not Paypal issues. Paypal is there in support of both buyers and sellers, but has traditionaly given the benefit of the doubt to buyers. They have recently made changes to support sellers, much like ebay has, as ebay owns Paypal and ebay is canvasing for listings and sellers.
The bottom line is caveat emptor - let the buyer beware. When you buy or sell on ebay (or anywhere else), you need to do your homework to protect yourself.
I have bought and sold a lot of stuff on ebay and on the internet, mostly without incident. I have had a few situations where Paypal shafted me because of a lying idiot, but thankfully, I was able to demonstrate to Paypal that this was the case. So although I have been frustrated and had unpleantries to deal with (both Paypal and ebay), it has all worked out for me at the end of the day.
Buyers - make sure the seller has enough feedback to satisfy yourself they are legitimate, or feel comfortable taking a chance. Makes sure you get hi res shots so you know exactly what you are buying - didn't John Lydon sing words cannot express. Make sure you get a tracking number with full insurance. Make sure the seller is openly communicating before your purchase. Make sure your purchase is covered entirely through Paypal. I genereally open communication with all sellers before bidding.
Sellers, you are now protected even if the buyer's address is not confirmed. Only ship with tracking and full insurance. Make sure the buyer has open communication before shipping. Keep all of your emails. If the buyer is suspect, dont complete the transaction.
You do have to be aware of and adhear to the requirements and processes of ebay and Paypal to avoid frustration and cost.
ebay has its own issues as well, including hijacking of accounts (happened to me) and issuing warnings instead of enforcing its own rules and regulations. They claim a transaction / bid is a legal contract, but they will not support you in enforing it. ebay will not force someone to sell something from a completed transaction. They will get 3 warnings and then possible suspension. ebay's problem is they use legal and fun together to describe their community. if you dont get enough for your item, just refuse to ship it and there is no long term recourse. The other thing one can do is say it broke and not complete the transaction.
I have completed several hundred transactions, including about 10 guitars without incident. If someone wants to sell it and someone wants to buy it and they are both normal, respectuful human beings, there should be no problem. ebay is the ultimate place for used and rare merchandise and there are many good deals to be had. You just have to be careful and patient.
Good luck with case glocke.