Last year i did some rockwell testing on 3 different cams, one older solid flat tappet Bullit with more than 100 passes on it (still good) it checked 45/47 on the RC scale, i checked a failed hydraulic comp cam newer and it checked 39/41 on the RC scale, i also checked a comp cam solid roller, it checked 58/59 on the RC scale, I also checked solid and hydraulic flat tappet lifter, theu all checked 58 on the RC scale on the bodies. I also checked solid roller lifters on the body and they checked 43 on the RC scale. I have in the shop a certified Rockwell tester where i work.
All the flat tappet cams are failing from most of the mfg'er and they blame it on the lifters, that's just not so, it their HT method and the fact that they used to nitride the cams but now they are cutting cost and won't gurantee anything, they just set back and say O'well. I think the big push is to go hydraulic roller stuff because they make a ton of money on them.
I used to run Compcam roller cams but i no longer do, but stil have a couple laying around,
I personally run Bullit cams and that's what i use on engine builds, they have been good to me and for me.
JMO
Zip.