I have a Block Rocket which is the Q.nigue machine. I love it. Never have tension issues. I have it serviced locally at a dealership so have never had to send it to the company as many have said. The only time I had a problem it ended up being a problem with the frame. I had one of the older wooden frames and one of the rails had become crooked. Got a new 10 ft frame and haven't had any more problems.