I have an 8x and a 10x and they have a solid build and have just come back from a tough 3 weeks visit to Islay. They have been knocked about on North Uist, Benbecula and South Uist, Ardnamurchan and many other rugged places and they just eat it up.
One thing that confuses some folks. The weight of the SF has been shifted to the eyecup end by reducing the objective lenses and by the addition of a field flattener in the eyepiece. It means the handling is superb and the weight is contained within your hand rather than being out at the objective ends like a heavy pendulum. This means when you pick them up, they don't seem as heavy as other binos and I have heard some folks say they don't feel as well built because they don't feel as heavy. But this is a deliberate design choice which means the handling is so good I can watch Otters for longer without having to lower the bins to rest and can hold the SF 10x steadier than some other 10x.
Any more concerns just ask.