I have some research recently exactly the combo your are mentioning share my thoughts as below:
FluidFlux - Clear roadmap (URL: Trello) , more realistic but relatively higher resource intensiveness, work perfectly with ocean, river, lake, waterfall, etc. BUT open world ocean is not yet official supported until v2.2 which is still WIP.
Oceanology 5, also a good ocean plugin. If you need river support you need to get Riverology (URL: https://www.unrealengine.com/marketplace/en-US/product/riverology) with additional cost. I only get Riverology 1 youtube demo online, thus I am not sure if it’s good enough to use since I see no demo for v.2; more importantly, their discord reply is extremely slow (pre-sales questions) so I have no hope for after-sales support. Just get what you have, documentation is quite oudated, no roadmap and I guess the good developer is only solo thus he may only have time focusing on development, not documentation, youtubing , roadmap, planning etc. But it’s still a good plugin.
NinjaFluid Live : It’s actaully an VFX simulation plugin, not a pure water/ocean sim plugin; it has some decent water vfx / surface visual effect which can use together with other water sim to enhance the vfx / visual impact; surely a good plugin for fluid simulation such as Niagara Fluid. It’s good to have even you have chosen FF or OC, but it’s more focus on VFX/ visual enhancements.
Actually I will get all three of them eventually, all are good water sim/vfx that suits difference use case scenarios.
Sorry I keep editing this post lol, some new ideas flowing in;
if you need all-in-one solution, get FluidFlux. They have clear roadmap and top notch technology doing realistic water simulations, and they have good supports.
If you need don’t really need river-sim and not keen on realistic stormy ocean simulation, Oceanology is a good choice, and they are very good (at this time) at underwater visual enhancement; eg underwater godray, etc. Cons, their support is limited i guess due to limited dev resources.
NinjaFluid, I will not get it in first place only for water-sim, but if you need more VFX sim (water/snow/fire, etc) , it’s the only choice between this 3.
If you NEED multiplayer supports for water sim, Oceanology is your ONLY choice at the moment.
only Oceanology officially supports OPEN WORLD now, if you need open world ocean simulation, this is also the only choice at the moment.
ps. those water sim not natively support WS in globe / spherical planet mode . since they need 2d highmap to calculate / do the fulid simulation.
Just to add to this, I already own FluidNinja Live though I didn’t buy it for the water simulation. It also doesn’t support replication.
I’m very interested in picking up Fluid Flux:
Partial MP support – I think more to come but early days
Open world support (WP) is limited?
C++ version coming soon but it’s a separate product, so might be waiting for that before I pull the trigger. FluidFlux 3.0 is entirely BP which I think is fine.
All in one solution – dynamically flowing water, water falls, beach breaks, gorgeous shaders
Demo project you can download and sample performance on different scenarios.
FluidFlux Discord is more active relative to Oceanology. Both discords are on the quiet side actually, but I think there’s a limit to how much support time a solo dev can give to an ambitious product like these. Support is an important part of a purchase, so if I bought something today, it would be Fluid Flux.