The fanatec is quieter as its not belt driven and is just an electric motor with a steering wheel bolted to it.
The main reason for the racing seats is that for higher torque wheels, clamping it to a desk just isn't strong enough.
I raced on a G920 for years and it was fine. Only worth upping to direct drives, and the costs, if you really like it.
They're less known, but if DD is something for you, check out Moza. Less well known than Fanatec but good quality and less dear.