Hopefully you are acquiring the pup from a reputable breeder who does necessary health tests (CERF, OFA etc.) on the parents to make sure they don't pass on any genetic defects or genetic diseases that could be a danger to your pups life and well being. The parents should be proven working farm dogs or titled in something (confirmation or herding).
Border Collies and Maremma Sheepdogs are both breeds that NEED a job, usually herding and guarding livestock but other dog sports may also be a good choice if other daily training and exercise can be given for several hours a day. Both are highly intelligent breeds that will keep you on your toes as far as keeping one step ahead of them in training. While boarder collies are considered easy to train if they aren't given guidance and proper training they will find their own forms of entertainment. Maremmas are more likely to make up their own rules and aren't as willing to please as a collie.
Maremmas are one of the few dogs where I think it is absolutely necessary to have a yard and a large one at that, at least a few acres. While most dogs would do fine going for a few walks and play with their owners, Maremmas and Border Collies do not fit that description. They are both "high energy" breeds that need to run and have several hours of exercise everyday.
Maremmas are heavy shedders and need daily grooming to keep their coats from matting. Border Collies coats are a little easier care but need at least weekly brushing to keep shedding to a minimum.
Make sure you have the time and energy to devote to this mix and have a plan for providing training and a job set up for them as they mature.