I am 51 and not in great shape but I use it and I have a blast with it! If the people in question like the music selection I say go for it! Also look into the broadway one for a different selection of music.
My neighbor is in her 60's and has many medical issues and replaced body parts and she does it. I have a bum knee and I just modify the moves and really love it. I just got it for my parents too, both in their 60's with medical issues. You should have no problems. If you have bad legs or something, it's completely possible to just do arm movements and still have loads of fun.