I've had experience with 2 Cover Pools covers. One is over 30 years old (and has nylon ropes) and has the fabric replaced and rebuilt more times than I can count over the years, and the other is the brand new on on my new pool. The new Cover Pool covers use stainless steel cable, not aluminum. I'm not sure that will really make much difference over the lifetime of the cover. On the old cover they typical failure mode is that the fabric gets worn and frayed where it is wrapped around the rope in the track. Most likely this is due to the dust that accumulates in the track (this cover is in the Southern California Desert). Once it gets frayed the force required for the motor to pull it grows and eventually there is a 1/4" roll pin that snaps. I don't know if the new covers still have that feature or if they have come up with a better way to protect the mechanism from too much stress. I suspect that the under-coping tracks will have less issue with accumulating dirt that than the deck top tracks.
In any case I would strongly recommend a cover for the water and energy savings, as well as the safety aspect. As for which brand, I would choose based on which has the better support in your location, as it will need periodic maintenance.
