San Bernardino pass is great for twisty, good visiblity road on both sides with the Hospitz cafe at the top
Came over here in July 2010. North to South. Traditional hairpins up and excellent pins and sweeper mix coming down on the south side. Not too much going on at the top. Ie. there is a restaurant but not much else and very little sign of tourism. Not much traffic either as the tunnel alternative takes up most of the cars. Come to think of it, when you pass the lake just after the top, it looks a lot like Scotland, just warner ;-)
Approaching the San Bernadino pass from south, there are a lot of wide bends with much to see, like waterfalls or idyllic villages. Driving closer to the pass the bends get narrower. On top of the pass, the scenery is otherworldly as you are above the tree line. Riding down on the norhtern side, there are some tight bends and hairpin curves. Further north is the beautiful Viamala gorge with awesome bends and nice cliffs. Watch out for tourists on the road around some of the parking areas.
Its easy to miss the the main road in the northern part and end up on the motorway. The motorway on the southern side is a good alternative to the main road and can also be fun. Its probably the most twisted motorway in switzerland.
The pavement is superb all the way through.
Overall, these 90km from Bellinzona to Thusis are absolutely worth every single meter. You e driving through three different types of scenery. From the swiss-italian valley to an alpine pass and last but not least the gorge. Its a microcosm of what you can get in the alps.
As there is a motorway alternative to this pass there isnt that much traffic and as the surface is good mostly and there are loads of hairpins it makes a nice road for bikes (if a bit narrow in places) The straight section of road between Hinterrhein and Sufurs joins up the two most interesting bits.