DAZ Dynamic cloth workis in DS3 only if you are not on a Mac and only if you are not running it in 64-bit. So, yes, it works for a lot of people.
I think there were changes for DS4, Mac useres finally got access to it in DS4 and I think it runs in 64-bit, but I don’t know whether the old plug-in is needed in DS4Pro. I think it may be built in now. Or at least certain basic functions are.
I’ve not been willing to undertake the aggro to try to use it yet though.
When I downloaded the latest version it was a separate installer contained in the zip. The zip contained the ds4.5 plus about 4 plugins.