Cable driven slide systems allow for lighter trailers because the main beams do not have a large hole to accommodate the drive shafts. The net result is a lighter frame without compromising integrity.
The cables themselves are fairly reliable. They do require periodic adjustment, however it is nothing to get excited about.
Occasionally a cable may fray and break (this most often occurs if cables are never adjusted)
Cable Repair/replacement kits are sold on Amazon.
Cable slide systems are less of an issue now because the bugs have been worked out, but more importantly the techs in the field have become more familiar with the systems and are able to adjust and repair them properly.
Keep in mind traditional systems are not foolproof either. As long as there are moving parts there will be wear issues and failures on both systems. At this point cables systems are just as reliable as shaft driven systems.
I have just completed my 3rd season with no real cable slide issues other than 1 adjustment that I did myself with the help of an online manual.