We have/had both. We had rotties to start, 3 to be exact from a show breeder so likely a little more social than most and at the start this was fine for us. They were our first large breed and we took them anywhere and everywhere and them being social was hugely important to us to combat the bad reputation in our area (was right around when a 4 year old was mauled by 3 of them).
As time moved on I wanted something that was a little more protective and found the Cane Corso. It took a bit to locate a breeder and when I did she still advised me to check out other breeders, talk to people about the breed, if I could get out and meet them. If I was still interested after that to contact her and we would look into seeing if there was a dog that suited what I was looking for.
Comparing the two was like apples to oranges, it isn*t really fair. My rotties were from show lines and while I loved them and it broke my heart to lose my last one a little over a year ago they were not the overly protective dog that people portray them to be. That is not to say that they can not be, as I know there are breeders out there (like in any breed) that still breed working/true temperament rotties. They are just fewer and far between because those puppies are not easy to sell/place, everyone wants one that looks like a rottie but acts like a lab. My rottie breeder actual imported working lines not long after we got our puppies and those dogs were serious, and would truly bring back an appreciation for what a awesome breed a rottie is.
Dealing with my corso in comparison was night and day. My first corso is a b*tch to put it mildly! She tolerates no misbehaving in her house, those that attempt it are quickly put in their place. She tested us good for the first bit and every once in a while gets it in her silly head to have a go at it again (7 years later) but gives over when she realizes that it still isn*t her day
My corso for the most part are still social, we like to show them and take them places and of course that is easier with dogs that are more social, we have some that are more cautious and those ones while socialized they are more cautious and don*t run to greet people. When night time hits, all behave differently. They go outside with a more cautious and alert nature and they check things out even while doing their business.
Training I found both pretty quick to learn things, the corso just as quick to learn stuff you didn*t want them to know but also more than willing to work on their own without having to be guided through everything, and a couple more than willing to tell me off if they feel like it, to which we have to have a discussion about who is the boss
In the end it will come down to just like everyone said finding the right breeder. In both breeders there are soft dogs, unstable dogs and hard as hell dogs being bred. You need to find a breeder that is breeding what you like, talk to them. You might not want a dog shipped but most breeders have a waiting list so the potential is there to fly out and meet the parents in advance, that will also give you a sense of the other dogs in their kennel as well.
Good luck with you decision, it wasn*t an easy one for us as we still love our rotties but the corso have stolen our hearts.