I think you put it in the wrong section on this forum too!! Moving now.
Were you using the rubber strap piece also, or just the arms?The short, and perhaps obvious, answer is not very well. It held my Samsung S4 with no issues. It ended the life of my first iphone 6+.
Here's a video with the full story and the crazy aftermath. Luckily lessons were learned and nobody got hurt!
Let me know what you guys think!