Just received this today and was initially disappointed to find the nut on the suction mount was missing. I didn't want to bother with the return so I treated it as is. The hole saw bits worked well and I was able to drill the 10 holes required in less than 2 hours. I have no idea of its durability, but the two bits I used have less diamond coating than when I started, so I'd be surprised if I could drill too many holes in both.