I recently got myself a E3D v6 hotend, I do believe that is a nice hotend. but what I did notice was that the supplied groovemount was not that strong, it actually broke (though the nice people at e3d replaced it).

Also the other groove mounts all needed some sort of friction, slide in action. That created wiggle. I made this one that can be fastened using 2 M3 hexbolts, leaving no room to wiggle whatsoever.

The STL provided works perfectly for my E3D v6 3mm Direct feed.