If I ever build another hydraulic flat-tappet cam combination, it will not have one of the "latest and greatest fast rate of lift" grinds in it like COMP offers. Between the valve train clatter I've heard first hand and enough dyno evidence I've seen over the years to show how those things start "crashing" at high(er) RPMs, they're on my "never use" list.

There are still some relatively high-lift .904 hydraulic profiles available from Crane that are less aggressive and smooth enough to not beat the valve train up so badly. Crane calls them their H2 series in the most recent Master List I have.