How is The Mini-ITX case Silverstone RVZ01 most Mini-ITX has bad airflow but this case has been called the best ITX case will this case make my pc's life short or is the case a nice case
(as nice as a ATX case)
It depends on what you plan to do with this PC you are planning on building. For heavy gaming it will be pretty bad, for light gaming (like browser games) it will be fine too, and for movie player set up then it will be perfect.
It's a great little case. Space is a little tight so installation is a more involved (might be a little tricky if you have big hands). Besides that, if you follow the build order in the instructions there shouldn't be any issues.
As far as air flow is concerned, as long as you stand it up on its side instead of lying flat, it should be more than adequate. You definitely can play more than just browser games. I've built a steam machine with this case and have had no issues with it.
Personally I believe this build will be a hot box, putting a 970 in a tiny case doesn't sound like my idea of good. I would also imagine that you are getting a top of the line intel processor too right?