The overall weight of the hyd roller lifter is not as much of a concern to some as the effects of the oil inside. It's eluded to here and in other tech articles that discuss the "lash effect".....
"But hydraulic lifters are far from the best way to make max power. That's because, as engine speed increases, the hydraulic lifter's plunger depresses further into its body due to the increasing forces of trying to accelerate the valve off the seat. The cam begins to act like an aggressive solid design from the lash that's created, but now has a shorter duration as the result. The more aggressive the cam acts, the harder time the valvespring has controlling it. As it approaches max speed, the valve bounces off the seat and oil rushes into the lifter to take up the clearance that's now been created at the plunger. This effectively holds the valve off the seat, (valve float), bleeding off compression and power, and limits the high-rpm capacity of hydraulic designs."
( I'm not necessarly agreeing whole hardely with this material, again it's just fodder for conversation. And this is at least 4 year old info, much has changed and higher rpm operation is becoming more commonplace. Especialy with new valve spring tecnology )
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