Fluidos
in The Commons
i put the first version ( now at 50%) in my wish list but i hesitate because it seem a bit complicated
Some user of Fluidos can comment his experience
And what about Fluidos 2 ( more expensive version)

Comments
Hope you noticed this minor detail: "Plugin needs to be installed through Daz Install Manager."
Currently, there seems to be an issue with the serial number, Daz apparently sent everybody another Fluidos S/N instead of a Fluidos 2 S/N, so, as far as I know, nobody has tried it out yet. Now, I have been using Fluidos for a few months and from what I've seen, I really can't recommend getting the first one instead of the Fluidos 2. You should check the product's thread to see some comparison images
https://www.daz3d.com/forums/discussion/366451/fluidos-ii-for-daz-studio-commercial/p1
As for how hard is it to use... I wouldn't say it's hard to use, but at least the first one required some experimenting to get the results you wanted, which means simulating several times with different parameters. But I'd bet that's pretty much the case with any fluid simulation tool until you get so used to it that you can set scenes up with less trial and error.