I probably used the Nimbus for 30 years and after having turned my ankle twice over a 20 year period i thought i should try something more stable. Right away i could feel more stability in the heel area with the 3030's.. Plus my foot seemed to sit down more into the shoe.. I can't blame the Nimbus totally because i think alot had to do with the fleetfeet inserts i was using. They had me to high in the shoe.. And when i was doing some cross country running my foot turned when coming up a hill and turning..  I'm 5' 10" 180lbs.. I like these shoes i think they do give me more side to side protection. Where as the Nimbus was a little more flexible but not much protection side to side.. The 3030's seem to have good flexibility for being more stable.. i like that