I have an SM-3 deluxe in cream and burgundy, beautiful machine. Slightly heavy shift, at some point I will replace the counterbalance springs,  bit it's ok as it is  mine has 12 pitch standard type.  I have a later model with a cursive font. My favorite for actual typing is  an SM-9 deluxe, I think an earlier version.  I am sure you know the SM-3 has spring cushions in the keys.  Olympia used these in their office machines.