You seem to have done a good bit of research. What are the health problems each breed is prone to? What health testing is recommended for each?
I meet folks walking with a couple of each breed. The RR owners try to stay away from other people and dogs. This breed is used for protection and they can be too quick to take offense to another dog or person. You would have to check out the breeder very carefully as to the temperament they breed for. I suppose these are nice dogs but I don't stick around to find out since my dog is with me. They are beautiful dogs and they are much bigger than my Lab.
The GSP owners I meet find their dogs need lots of off leash exercise. That's easy to do where I live but is it where you live? I meet two of these, both usually many feet in advance of their owner as they both run, run, run, hunting out smells even though neither is hunted. Both, I only meet two so not a statistically significant number, but both are really nice dogs.
I'd like to stress the exercise. I have 100s to 1,000s of acres of off leash opportunities for my dog. When I meet the owners of these breeds we are all out for a couple of hours, for me at least an hour a day. I am out with my Lab for about two hours a day, off leash, about 3 times a week. The RR and GSP people are too. I also work my dog in Working Level Rally-O where I have never seen a RR or a GSP. Exercise with no brain work just doesn't go as far to making a good family pet dog.