The difference between getting a 4-way handshake and cracking wps with reaver is a no-brainer. after you get the handshake you have to challenge it against a dictionary. if you dont have the exact password in the dictionary then it tells you it wasn't there. Not that you were close or even an almost. Ontop of that it takes a long time (even with gpu acceleration). I have gotten many handshakes and not been able to crack them and i've cracked them within 10 minutes. On the other hand Reaver is a guarenteed crack. It just takes time and a pretty good signal (basically if you got a handshake you have a good enough signal to use reaver). play with the options. sometimes if you have minimum signal its just going to take a few days, or if you have a good signal you will want to alter options for speed.
basically to crack any wifi it takes time and a little dedication jus tto learn the ins and outs. it isn't easy.
