If you just send money (probably 99 % of people) it looks as super legit company with good customer protection and it 'just works'. If you get a merchant account you will find out what true PayPal is all about and you will eventually Pay, pal.
My suggestion is stay the hell out of it - the rules are not transparent and are bent all the time and they can do whatever they feel like, with payment processors (processing VISA/Mastercard) you can at least choose from multiple but once you 'hook' your customers on PayPal it's over.
Just my 2 cents - everyone I know had at least once at some point their PayPal account frozen (ofc the merchant account).
This is true, if you use paypal as a payment processor you are going to get a very good impression of paypal, but if you are selling stuff on ebay or something sooner or later your account is going to get frozen even if you are a legitimate business.