It's the new e-gold - which was essentially boycotted after it was accused (and rightly so) by the FBI, CIA, INTERPOL and several other international law enforcement agencies of money laundering and funding illegal sources such as human traffiking, drug traffiking, fraud and others. Even though the majority of these crimes were committed by the users of E-gold; the company got the blame. A modern day "blame the tobacco company for making us smoke" scenario.
In other words, it's a great, cheap way to transfer funds as long as you realize you will never get your money back if you get scammed. If you read the user agreement properly you will also note that they can run off with your money and everybody elses at any time, no more securer than a common HYIP scam but alas they will not shut down any time soon and I know several people who have moved millions of dollars through Liberty Reserve with no trouble.
TLDR; it's good if you realize it's going to cost you min $30 every time to cash it out to WU.