Driving lugano to interlaken and back . The return route has to the quicker as we have a train to catch. So we will might on pass in one direction and the other pass in the other direction. Any thoughts?
I haven't been over the Furka pass so I can't speak to which is better. I did love our drive over the Sustenpass, though. It was beautiful with a lot of places to stop and soak in the views. The road is twisty, like all the passes, so the driver will need to be alert, but it wasn't overly challenging other than that.
The Furka route is much better, because it is followed by another very impressive drive via Grimsel.
Alternating routes on your way in and out is a wise choice to get the best of scenery.
I've been over both passes in a car. Furka is exciting. I have some videos of coming down Furka in a post bus. I can send them to you if you contact me privately (hoping the files aren't too big to send).
We know of Swiss residents who take visitors to the Furka pass to scare them, but also support your idea of trying one each way, if weather is good.
Both are very scenic but I much prefer the Furka.
I drove over the Furka pass last summer and it was spectacular! The road is very good but many, many, many switchbacks - although I've been over passes in the alps with more than this one. Stop off at the Rhone Glacier if you have time and see the effect of climate change firsthand...it's a shadow of its former self. They've covered part of it with giant tarps to try to keep it from melting - not too successful I'm afraid.