I'm not a contractor but I have both installations like you describe in a dbl shower: The left has one rain shower and three jets and the right has one rain shower and one hand-held.
The cost depends on (1) what mfr you select because this determines the piping (labor cost) layout, number of valves, other parts (parts cost) etc. However, the main difference is that a hand held water output exits the tile one in one place (plus the labor to attach its other end to the tile) while the jets exit in two separate places. (2) The cost in tile cutting one vs two holes.
Overall there is too much difference in cost.
A word of warning. I have a post just going on how a plumber should install the shower / jets combo. Be sure to get someone who has had experience in your layout.
Hope this helps.
Sparkman
