I have Realflow 10 Standalone and don't know how the C4D plugin compares to it or X-Particles. At that time, I saw no reason to get the plugin if I had the standalone version, esp. because the plugin only contained Dyverso solvers whereas I was using Hybrido mostly.
My X-Particles maintenance expired in the first half of last year, so I still am on a pretty recent build. Maybe I should check the solvers out. I think they also added a solver to NeXus, but I need to check if I have that one.
Did you ever use X-Particles fluids, Dave? Whenever I watch a Bob Walmsley tutorial, everything seems so easy, but on my own, I am completely lost in the multitude of options which seemingly appear as copies of themselves in half a dozen places. I just find it so difficult to learn.
The core X-Particles system is very user friendly IMO. Place an emitter, add modifiers and, if needed, determine next steps with questions and answeres. But it is within the settings of each emitter, each modifier, each tag that I get overwhelmed and start to question the usability. For me, it's all too similar, too much, too nested within the object's settings. I wish for a more simplified, more unified approach and a bit less diversification.
It will be very interesting to see what Maxon will come up with.