aikijutsu vs. aikido
I know the difference between the two is that one is an art, while the other is a sport. One is based purely on technique, and the other is rooted in philosophy. Both mirror each other in many ways, but their are distinct differences.
I use aikido techniques as part of my taijutsu training. It's clean and easy to learn, but I do recognize the limitations of these techniques in a realistic "street fight" situation. That is where aikijutsu comes into play. It is the practical application of these techniques in a real-life combat situation.
I had a friend who reached blackbelt in aikijutsu. His dojo was really hardcore and they trained full contact. He had multiple bones broken during his training over the years. He was attracted to aikijutsu because of the realism and practicality, but I think he eventually realized that the fight scenario he was training for, was never going to happen. And he was letting himself get beaten repeatedly for no real reason (and paying monthly to do so!)
I think this is a limitation with a lot of martial arts. You can train and spar in unrealistic dojo fights, or you can train for real and risk injury and pain. Either way, you may be training for a conflict which may never materialize. If there is a spiritual/lifestyle teaching to it, then it can serve more of a purpose beyond the violence. I don't know if my friend ever wanted to learn anything more than just a really good way to kick somebody's butt. Maybe that's the difference.