I think most everybody prefers a disk brake on the front. Its stronger and works well in wet weather. If your front wheel needs truing, you can still brake well (rim brakes don't work well on wobbly wheels or if your rims get greasy).
-On the other hand, over half of the motorbikes on this site have front rim brakes and do just fine.
Installing disk brake up front will normally require the purchase of a disk front fork and disk front wheel, in addition to the rotor, caliper, cable and lever.
I ran a drum brake on my gas motorbike.
On my e-bike, I'm sticking with the rim brakes and putting that money toward some better batteries.