I am not a cam expert, that being said I believe the main difference is in the lobe profile.
The ramp rates determines how quick the lifter opens the valve, this can be an issue as some lifters can not tolerate the faster ramps. There is also part of the lobe that is the take up ramp where the valve is taken off the seat this is very differant on Hyd vs solid cams.
Have your cam reground to a solid profile?
Food for thought
