I'm not Zuzu but I can answer part of your question.
Own-root roses are just that - roses that are grown on their own root system vs. grafted roses which are roses that have been grafted on to another roses root stock.
Example: 'Joseph's Coat' rose grafted onto 'Dr. Huey' rose root stock. If, something happens to Joseph's Coat - (weather, over zealous pruning, lawn mower accident, etc) that takes the rose down to the ground/root, next year you will likely have a 'Dr. Huey' rose growing.
One of the pros of grafted roses is that they generally grow more vigorously, at least for the the first few years. 99% of the roses that can be purchased at the big chain stores (Home Depot, Walmart, etc) are grafted roses which are much cheaper (and more readily available) than the ones we all rave about on the "what we ordered" threads.
I have both. I like both, however I live with an over zealous pruner - bless his trying to be helpful soul - so I have been purchasing more own-root roses the past couple of years
There are many more pros/cons and opinions out there. Hopefully others will jump in and provide their experience! Edited to add: I have 5 'Dr. Huey's' in my yard - I have never purchased a 'Dr. Huey' rose.