I guess direct drive trainers are best in class, when we talk about "low noise"?
I wouldn't say so and I don't believe anyone has actually said that on this thread. I have a Wahoo Kickr and compared it to a Neo. Both made enough noise in hard workouts that I at least had to raise the volume on the TV a bit. I have a KK Road Machine with the large flywheel and find that with the right tire (no tread, preferably a trainer-specific tire) there is still some noise and, as for the Kickr, needs the TV volume turned up a bit. With an InsideRide/eMotion roller set we experimented with, there was a fair amount of noise, again, about the same as for the two trainers just mentioned. A TruTrainer roller was quieter, and possibly the quietest of the bunch (both with the flywheel attached and without). The eMotion drums were smaller so the ride quality wasn't quite the same (smaller drums, whether on a trainer or a pair of rollers, basically makes the tire feel like it has higher rolling resistance, so they make the ride sluggish). Nothing I've tried matches the TruTrainers for road feel, quiet, and the ability to do a hard workout. If you get ask them to add the magnetic resistance to the flywheel on the TruTrainers, you get an amazing hard workout with great feel, and not much noise.
The Elite fluid is one we tried only briefly. It happens to be very quiet, but we didn't think it gave the same kind of resistance and rolling feeling of some of the other trainers. The 1Up is nicely made, but the graduated resistance mechanism has some internal lag to it, which both feels like excessive rolling resistance and in some cases causes something like a bad transmission shift, when it won't shift linearly.
If I was reducing all the training tools here down to a minimum set, it would be TruTrainer rollers with flywheel, KK Road Machine with the large flywheel, and for erg simulations, the Wahoo Kickr.