Ive used it (SK78 max) on the forestay and caps of i14. I kept wire shrouds so I had one constant in rake / rig tension measurement. My observations would be that it is relatively light, cheap, durable and easy to use/inspect.
Downsides would be that you probably have about 100mm per stay (~7m length) of constructional creep on the first couple uses before it settles down, i.e. the splices and weaving settling down.
After that its pretty stable, and viscoelastic creep is a function of % of BL, and time under tension. You won't be using more than ~ 30% of ultimate capability really and also for a few hrs at a time, so its quite negligible. if you take rig down and coil it up you regain some of that so it'll feel tight on same numbers for the first sail or two off the trailer.
Apart from that it hums like hell. Mournful at low wind in dinghy park, feral banshee like at high apparent winds, that energy must be subtracted from your boat's kinetic I reckon.
You can rub those sticky gloves up and down it to play a tune like on a harp if you are bored.
I could see myself using it again.