Congrats on the new bike!
The only reason to get a full-face helmet is for the extra protection. They're also a little quieter, but the big reason is because they protect your face in a crash. A 3/4 helmet, even one with a shatterproof snap-on faceshield or something similar, will protect your skull but not your face (the shields just don't stay on in a crash--they will keep stuff from getting thrown into your eyes while you ride, but they're not crashworthy). You can get some pretty fucked-up facial injuries in a motorcycle crash, as I'm sure you can imagine. OTOH, 3/4 helmets are cheaper, cooler in the summer, and easier to store in a saddlebag. If it were me, though, I would (and did) buy a full-face helmet.