I'll have to disagree with many of the posters in this thread. The early 70s pianos, before the bump mod, had a heavier action much like that of an acoustic piano. Given that I play both, I liked the heavier action. BTW, I never found it sluggish. Perhaps the sluggishness other poster refer to has to do with lack of lubrication, worn felt, keys that need easing, or some other issue that can be addressed with proper maintenance and adjustment.