It is a great way to protect your hair, as long as you get it done the right way, and handle it correctly.
I used to always get cornrow and sew weaves. My hair only got messed up after I took it out and started manipulating it again.
If you really want to keep your hands out of your hair, try putting in a CLosure piece, or Master parting with the cornrow and sew method. I am not sure if you are familiar with these, but it has a natural skin part, with hair coming out of it. Do a quick search and you will see more info on these pieces. Another benefit with these, is you don't have to try to match your hair color and texture to blend in with the hair you are putting in, just get the closure piece to match. All of your hair would be in cornrows. I don't have first hand experience with these pieces, but I have seen the designs, and many have fantastic results.
Sindeee also had some good tips. She gets Kanekalon hair cornrowed in with her own to provide a stronger base. She also makes sure that no one rips in and out of her braids when sewing. That would cause major breakage. Make sure they go over and under with the needle.
Whatever you decide to put in, remember to brush through it gently. Yanking on it will pull on your cornrows and damage your hair.
HTH /images/graemlins/grin.gif