I prefer chains because they are much more easily adjusted for length, and a bunch of other reasons as well.
Safety chain length is a very important part of the system and is often overlooked. The chains, or cables, need to be as short as possible without binding up in a jackknife position. I'm in the process of doing this to my Ollie as I think the supplied chains are too long. Back up your trailer in a tight turn as close as you can without TV/trailer contact. Stop there and measure the distance between the two mounting points, chains crossed. I will do this with the actual chain and connecting hardware I'm using. Leave just a little slack, maybe one link. I'm hoping that when I drop (lower gently that is) the trailer off the ball mount, the attached chains will prevent the trailer coupler, and the mounting hardware for the chains on the trailer frame, from ground contact. We'll see, there is only so much one can do if the design is off. This chain/cable length will be different for each TV/trailer setup. So supplying one length that "fits all" is not doing anyone any favors and could be hazardous in an emergency. If you have an articulating hitch, that could be very different, but I have no experience with those. Just my 2 cents.
Dave