Welcome to the forum, you've come to the right place! By hub brake I assume you are referring to a drum type brake, similar to the older motorcycle type, rather than a disc brake which mounts to a hub?
If this is the case, the drum front brakes are fairly powerful stoppers, about as good as a V-brake upfront. For the rear, your not likely to find a drum brake per se.....a band brake yes, but I feel a V-brake is a bit more powerful for stopping and better yet is a disc brake. Coaster brakes I find a bit touchy as they really don't have much modulation in that they lock-up and skid, and that can be exciting to say the least.
I personally like disc, V and drum brakes, but some times you are limited by frame bosses, front fork type, cost and the ability too fabricate. One thing's for sure, you need a lot more stopping power on a motorized bicycle than you do on a pedal only bike.
Here's what I prefer up front, it's a disc and a V-brake controlled by a single (double-pull) lever:
On an aluminum framed beach cruiser with a 49cc 4-stroke motor....
EZ Motorbike Dealer - San Diego, CA.
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