The "real" difference in how "lazy" the comp is in comparison to the 484 cam are the differences in the checking height for the advertised numbers.
For the Comp it's clearly stated in the lobe specs that the advertised number is taken at .006" tappet lift.
I haven't personally measured a 484 cam, but the 509 cam I measured, that supposedly has "292" deg advertised duration actually measured 305-306 when checked at .006 tappet lift.
Within the same lobe family as the 280h, a lobe with 305 duration at .006 gets you .525 lift with a 1.5rr, and 253 @ .050.

I doubt the 484 cam actually has a lobe that's any faster than the Comp 280H....... It's just a bigger cam(longer duration), and that's where any power gains would come from .

"If it were me", and I wanted to make a real improvement in performance over the 280h, I'd put a solid in it.

To make any kind of valid recommendation for a cam, solid or hyd, I'd want more info about the overall combo.