I use a TM Warthog joystick and throttle, and the mouse just for looking around.
Ugh, mouse for ship control just doesn't work for me, I end up chasing that little orange triangle all over the shop and getting horribly out of shape (same problem in SC).
I think if a PC owner was considering a component upgrade, a joystick upgrade should also be considered just as video card/cpu/memory. If you're a heavy flightsim gamer, it makes sense, but it just depends on the 'priority' if you like, of the enjoyment to be had in ED vs just getting by with the mouse control.
Mouse control can obviously be very good (I think SubSynk uses mouse, or was in one of his Twitch streams I watched)...