Hi @Spoonraad That’s a really good question. At the moment, I’m running the Buttkicker simply 'Y’d off of the audio. It does a good enough job for engine vibrations and a couple of other effects … although it can be a bit strange if I’m enjoying some nice rock music to accompany my scenic flight 
Sounds like using SSA to drive it adds a lot to the effects, although my rig is i7/9700 + 2080Ti - so I’m conscious of not adding too many ancillary processes under MSFS.
As for the V3 platform, It certainly adds a lot to the effect, although at a very hefty price. If I’m honest, I would say I get more from the Buttkicker than the V3, at about 1/10th the cost. If I didn’t already have one, would I spend the money now? I’m not sure about that.
There are a couple of areas where I’d expected a bit more from the v3. Now, to be clear, this is not related to the hardware which I think is excellent; but to the driver profile (and possibly limitations from MSFS telemetry): Except very occasionally, there is no sense of turbulence (even some random mild lateral rocking would add a lot…); the platform seems to be driven more by aircraft’ orientation rather than by acceleration; and the ground roll effects are odd - far too regular, rather like the aircraft has egg-shaped tires.
Having said all that, since I have the V3, I don’t fly without both it and the the BK turned on!
When I have a bit more time on my hands, might start looking at a DIY platform driven by FlyPT. If you haven’t already seen it, take a look at the link referenced above for some inspiration!
Happy flying!