What I am curious to know is what, if any, usability improvements have been made in the subsequent two versions that would justify spending the money to upgrade.

So I don't need the new acceleration features.

My computer seems fast enough with the older version and I am happy to leave it rendering while I go for a walk. My expectations performance-wise are not the problem. CorelVideo is still a great product but even more unstable (in my test of their latest version). Well here I am 4 years later and with spare time on my hands - giving it another bash. And I even paid for an upgrade in early 2019 that puts me on Video Pro X V17, so I am guessing two releases back. So I read about Pro X and it seemed to be a decent fit at a good price, but of course neglected to install a trial that would have told me it was no CorelVideo in the ease-of-use dept. But it was horrendously unstable and produced shockingly poor renders of my GoPro and Canon EOS 80D footage. I had moved from CorelVideo'pro' that is a breeze to use, being supremely intuitive for idiots like me.

I bought Video Pro X on a whim in late 2017 and instantly hated it, finding it difficult to grasp.

Magix vegas pro v17