My comments relate to Computrainers only as I have not used a Kickr, mind you a number of my friends have them and are happy.

I currently use my 2001 model Computrainer exclusively using PerfPro software, so I' think I'm at the current high water mark of software. Racemate stuff, is basic, but still works.
speaking of works, the unit I have has been in use since 2001, no updates, no repairs just one replaced cable from the local distributor, who I bought the unit from ( well my wife bought it as a birthday present - love my wife(still))
in another 14 years time, I assume the same computrainer unit will be operating, but what software will be in use I can't foresee... but I know that the unit, the basic software and the stand alone controller will still be usable. And still with the same wife....

if I was buying today at equivalent price, I'd get a Computrainer, but there is a reasonable price differential that further muddies the waters