I'd like to say to anyone thinking to quit the phd... don't do it!
I started phd after graduation here in Italy, then I left it after 18 months, because I cannot stand my tutor any more, and because my research group wasn't good at all (yes, I admit I didn't investigate enough before starting it).
Now I have a boring job, as a computer programmer, I pass all my days in an office, and I haven't any possibility to do anyhing interesting, because I haven't any contacts or raccomendations.
So.. follow my advice... don't give up your phd!