Modern Hydraulic flat tappets are much faster ramps than the older ones that made power more by maxing torque in the sweet spot and with realtively big but comapartively slow ramps. Mopar valvetrain is typically bigger and far heavier than the .824 Chevy and .875 Ford, that mass takes it's toll in terms of noise. Lighter valves (like the smaller stem edelbrocks and lighter valvetrain components upstream (retainers, bee hives) help up top in terms of rpm stability but down low for the clatter a lot of people seem not to mind I'd just as soon run a solid and have better response and cleaner pull on both sides of the scale.

The comp XE's and the like seem to make good power but they often sound awful under the hood. For Flat taps I'm old school but I generally prefer the older (80's era assymetrical)Crowers, Ultradynes and engle series hughes were also very good; after all the hype quicker ramp speeds on Hydraulics will really only get you so far compared to a solid and solids are a whole lot lighter mass, my preference has always been to really work the heads to max out that mid lift (.200-.450) 'sweet spot' and just keep the cam tried and true. I'll bet that the reality is 90% of the R&D for the quicker ramps is developed around SBC test mules and then simply 'scaled up' for the .904 mopar market

Noise and harmonics that don't 'sound' quite right even though they seem to function ok will always stick in my mind and ruin my driving satisfaction, you're always gonna be thinking about it.