I use these all the time for the grounds and permanent conections.
My 4 point Buchannon crimp tool is over 35 years old and still works like new (it gets oiled occasionally).
As with all connections, twist them first and I have never had one fail.
They are very easy to remove, just use the lineman's pliers from the side and flatten it down, then do the same 90 degrees from the first. Repeat this about three times and it will split right open.
