The top one is only acceptable when the brick is the same size or smaller than the size of a normal power plug. I loathe those massively oversized bricks that cover the two sockets on either side of it when plugging it into a powerstrip. Zero consideration went into their design.
In every other situation, the bottom one is vastly superior.
Longer cable.
Easier to cable manage.
Usually modular, so you can swap out the cable if it's damaged.