I went hydraulic because of fewer valve adjustments, and less wear and tear on the rollers. Not sure what performance gains are to be had, I have spun my engine near 8000 rpms with no trouble.
I think the biggest gain is from flat tappet to roller just to get that quick ramp and bigger area under the curve.
I am at about 10,000 hard miles with the hughes roller cam and lifters with nothing but good things to report.