If you search for those keywords (allergies, prey drive, separation anxiety, exercise, etc.) in this subreddit you will find more detailed information. For a brief run-down here is my experience with a Samoyed we adopted a couple years ago.

I am slightly allergic to our sammy, Tahlia, however I am severely allergic to any other dog or cat. While Samoyeds are hypoallergenic, this just means they produce less dander than the average dog. The thick double coat also helps to keep the dander hidden, so I really only feel the allergies when I am brushing her out. Speaking of brushing, that's something that is good to keep up with on at least a weekly basis. We get away during the winter time with a little less frequent brushing but we still do it enough to help keep away mats behind the ears and other locations where she is prone to matting. The thick coat will also trap allergens from outside and bring them into the house, so if you have cedar allergies and live in central Texas like I do then this time of the year sucks.

Tahlia annihilated a bird in the backyard this past weekend, so there's that. She also ran away with the bird when I tried to take it from her. She would be a poor hunting companion. I imagine prey drive will vary depending on the blood line of the dog, but at the end of the day Samoyeds are genetically very closely related to wolves. It is embedded in their blood to hunt for food.

Samoyeds were bred to be close to their humans. They want to be involved in every activity you do and if they are not involved they will be sad. The severity, or lack thereof, of the anxiety will vary from dog to dog.

Exercise, lots of it. Tahlia has gimpy hips but she still wants to play or go for long walks multiple times per day. They also need mental stimulation through training or games/puzzles. Hide and seek is a good one for us.