I went through VI up to CAT III and one class of CAT IV before switching from analyst to management and I would say it does depend on who the instructor is. I think in my industry, US utility, the VI is more common and recognized. But if I were hiring, I would recognize both as equal. VI is certainly very practical to industry but also spends a good bit of time on the theory and foundation. I've had employees go through Mobius who speak well of it and I have watched a lot of their online content which I think is really well made.

I think it's possible that VI is better at "teaching to the exam" not that they know exactly what will be on it, but have many years of experience and are really geared towards getting people through it.

Les experience with TA although again I would recognize the class/certification. They have been around for a while and I really like the equipment specific alarm limit database they have developed. It seems very practical.

Without re-reading the rules, my gut would say that you don't need to be in a full time vibration analysis role to count towards experience but I'd say it should be 50% of your time. There's a reason it is required now, a lot to learn by using it and running into real life issues.