TLDR: not for the faint hearted!
I've had almost 20 years experience of the HPR breeds (the breed group GSPs belong to) and currently have 2. They are a wonderful group of breeds, affectionate and capable of chilling indoors but they need physical exercise and mental stimulation.
Ours get about 35-50 minutes in the morning and another 40+ minutes in the afternoon, as either one walk or two, and almost all of that is off-lead. Included in that almost every day is a 10-30 minutes training session: basic obedience, retrieving (including directional work, memories and blinds) and hunting under control. They also get occasional longer walks - every week or so we'll be out for an hour plus.
They have serious prey drive, and they are bred to range wide from the handler, so if you don't understand that you have a long-range hunting machine you will have problems. I've worked hard with my two and they will now stay by me off-lead and watch a deer away, but I keep tabs on them all the time, every walk. They can wind a pheasant from 100 yards. They are happiest in work.
There are lines that have been bred with a strong focus on show and none on work in GSPs, short-coated Vizslas and Weims, and you could expect a puppy from such a litter to have less hunting drive and possibly just be an energetic pet who likes chasing squirrels. A good 95% of the dogs with working test or field trial winners or champions in their pedigrees are fantastically driven. They are eminently trainable (though by general agreement harder work than labs and spaniels), but you need commitment, dedication and a good gundog trainer (and probably the support, advice and encouragement of a club) to bring the best out of them.
Would I have another? Yes, absolutely. Was I prepared for what our first one needed? Not at all. Do I regret that dog? No, because I love the breed group.
Should you get one? Only you can make that decision, but they will eat time for the first 2-3 years - they are wild puppies and hyperactive adolescents. PM me if you have any questions. I am involved in a club and if I can't answer you, I'll be able to find someone who can.