Reports from Forum members and others suggest these were a quality product, however could mean what they were compared to then.

John had no problems with those he gave me,,,,but as we and he are now aware, his valve spring pressures apparently were lacking. My guess might be that hydraulic rollers and high(read standard now) valve spring pressures are not yet ready for prime time.

Given that most hydraulic roller failures seem to be due to collapse, and postmortems seem to indicate broken internal discs as I experienced. Solid rollers of course care not a wit about this as they have none of these very flimsy oil control discs to deal with.

On your point on spring bind on specific cylinders/valves. The previous failure that I experienced was on number 6 exhaust. Some 2K miles later it is still ok, which suggests if there was something unique about this cylinder/valve it likely should have failed again by now. The first failure was after just a few hundred miles which suggests a QC manufacturing defect,,,just as with this most recent failure. 14 others have not yet failed.

Would be enlightening if a manufacturer would chime in,,,,but for now it appears that their tactic is to keep their heads down.