I tried EC5's once a while back and I do remember some movement between the conductor and the plastic housing. The conductor was free enough to rotate it in the housing by the wire and they did wiggle a little in the housing. I like that they're basically a bullet in a convenient plastic housing, I didn't like how hard they are to pull apart though. If you're looking for a similar connector Castle's connectors are the same concept, never used them, I've been happy with Traxxas connectors except when it comes to soldering them up. Nothing is as easy as soldering a bullet though.