id take a look at more than just the cost per hour...
id look at the fact that the plasma will kick the shit outta both other machines in inches/minute...
then there are levels of quality - I know the waterjetter we deal with has 5 different settings on their machine - all with a different edge finish... the better the edge, the slower the machine moves, the more each job will cost...
if you really want to start moving through material though - a CNC Punch will blow all of these tools outta the water any day of the week... and can handle up to 1/4" material...