I think either of them is well worth fitting. They are a real good idea and give a lot of peace of mind, especially in windy conditions. When we did ours about 18mths ago the cost of both fitted was about $1500. We have the Dexter Sway Control (DSC) and are very pleased with it.
I did a lot of reading before fitting our l (DSC) and even though Kedron now fit the ALKO Electronic Sway Control (ESC), when we ordered our van they did not fit either. I got mine fitted by Vehicle Components (VC) in Brisbane for the same price as the ALKO ESC, VC would not say which was better, but similar to
@NoWorries I asked the installer and though he could not tell me which was better, he was fitting a DSC to his own van and they also sold and installed a lot more DSC than ESC. They both work by applying your van brakes to stop sway, the DSC applies one brake at a time to control the sway much like most modern car stability controls. The ESC applies both brakes at once, similar to you pressing the button on your electronic brake controller, to apply brakes to stop sway. Both methods work well, the DSC method is a little more sophisticated and in our humble opinion a better way to control sway.
The main advantage for us with the DSC was that on dirt roads the DSC has additional accelerometers which detect rough road surfaces and turn off the DSC to prevent inadvertent application of the brakes from bumps, the ESC solution is you unplug the 12V supply. So the DSC turns off and on automatically the ESC requires you to manually disconnect and more importantly reconnect. I called our caravan insurance company, CIL who give us a yearly premium discount for fitting either ESC or DSC and asked what would happen if I disconnected my sway control manually and forgot to reconnect it and then had an accident. They said I was the first person to ask that question and they were not sure and it would depend on the circumstances. I then asked if the DSC automatically turned itself off and on without user intervention while operating as it should then had an accident, they replied no problem.
The other advantage of the DSC is that it is powered from the van not the tow, which means if someone else tows your van without the appropriate tow power supply wiring (for the ESC) the DSC will still work. The ESC requires wiring of a seperate (Red) Anderson plug to power the ESC fitted to the tow and van. A warning is that some installers wire the ESC power wiring in spare pins the 12 pin plug, this could be a real problem on rough roads as you would find it very difficult to disconnect the ESC without disconnecting a lot of other stuff.
I am very pleased with the after sales service from Dexter's Australian agents. The DSC has fitted to the A frame an indicator LED which I broke with a stone (or trail mate jack). I called the agent and asked how much for a replacement. They sent one at no charge to a caravan repair place in North Dubbo which fitted for us for a small labour charge and relocated it on the A frame so it is harder for me to break it. Really good service from the DSC agent.
Another nice thing that applies to both the DSC and ESC is that if your tow is fitted with Trailer Sway Control (TSC) as is our Toyota LC200. Both sway controls do not interfere with TSC operation. The TSC in fact is a back up to the DSC and ESC, if for some reason either of them do not work the TSC will do its best to stop the trailer sway.
In summary do not hesitate fit either. We preferred the DSC for the above reasons and are very pleased with its operation and DSC after sales support after our 18 mths of use. Make sure you use an authorised installer and do not forget ask for the insurance premium discount. I have also heard a "rumour" that ALKO has bought out Dexter (Tucson in the US), so who knows what will happen next, they are both good safety technologies, they should be on all caravans from new.
