Thank you for your advice.
So I guess if I am willing to "buy" all the disadvantages when enabling snapshot, I can just as well use RCSI so I do not have to adjust all my query-statements?
Queries that run for hours sound like they need some tuning, just saying...
A single query is not running for hours but if we are calculating back a few month or years it can take its time.
We are talking about three-digit million to billion rows in those partitioned tables.
However I can not estimate how "bad" the disadvantages are.