The spring rates are good, and are exactly the same as the stock Bullitt springs (but shorter giving more of a drop). The dampers you use with them will dictate the ride quality more than the springs with the Steedas. They ride very well.
We have one customer who has the steeda comp springs with one coil cut out of all of them and it still rides better than most other lowered cars. He's using Bullitt dampers with that setup.