you know why i preffer the manual one, because i have full control of it.
i can change turation, direction angle and so on, without pushing buttons and so on.
with the electrial hand drill, for these kind of holes, you need a very small drill, no more than 10W, because if it is very heavy or big, you can easily destroy the pbc and the drill itself.
and one more thing if you have a single sided pcb, try to drill the holes from the part where is no copper, its easier like this.
if you hace to drill the holes from the copper side from various reasons, here is an advice....where you want to drill a hole, put a small nail and hit it with something, but not very hard, enough to make a small hole or mark, on the pcb. when you will drill the hole the drill bit stays fixed in the small mark that you made and wouldnt run away because of the turation.