Jannik,
I do not know much about Ari Ben Aviator. However, we've had many instructor come and work for us from North American Institute of Aviation. In the past three years we have hired many instructors and all of them were very good instructors. I spoke to all of them and every single instructor was happy with the school too. If you like you can check out their website at
www.naiasc.com
If you are willing to wait I suggest going to Naples Air Center. They are also part 141 school and I heard that they are waiting for their J-1 Visa approval.
Good luck with your flying
Cheers,
Jatin