I chose rear hub motor (similar to outrider) because it is light and efficient for what I do – mostly flat to very moderate hills.
Mid drive is the way to go if you have hills and/or need to use the gears. It requires more maintenance on the drivetrain though.

The only real disadvantage to 48v is the batteries are 30% larger and more expensive. May or not be a big deal. Of course they have 30% more power too, but yes if you don’t use all of that power you can go just as far on the same size battery. If you use more power, you will run out of power faster. For long distance touring, smaller is better. Personally I use smallish battery and small current controller because I have lots of power in my legs that I want to use, and smallish batter keeps it lighter, cheaper and longer lasting. Most people however want more power!

EM3ev is the way to go for a mid drive kit, or a midweight hub motor. For a light motor like the outrider, you can get a Q100 from BMSBattery, but don’t’ expect any customer support from them.

If you want drop bars you need PAS, with flat bars you can also have a throttle.