When you ask this question, you get a lot of different opinions. We can talk about spring pressures, oil, cam cores, lifter styles, lash, lifter maintenance, lifter brand, bushings vs bearings, etc, etc.
Certainly, which one to use depends on the intended use. The bigger the cam and the higher the necessary spring pressures that comes with that tends to favor the rollers.
For my primarily street Hemi, low maintenance and durability was very important. I talked to several major Mopar engine builders about which style cam to run.
For me, Ray Barton's recommendation of the tool steel flat solid tappet was the best choice. And it has worked well.
Not trying to be a smart a--, but have you checked the cam lobe nose ? me and others did not fair so well with tool steel lifters. I was going solid roller, I now am going with the Morel High RPM, push rod oil, Hydro roller.
