The only downside is, the lips are pretty short. So short in fact that slamming the mag in hard enough can make the top round rotate and fly out of the ejection port. So the gun require a little babying when reloading.
The design of the last round stop is pretty ingenious. As you might know, Glock had issues where they used a pretty typical indentation on the follower to drive the stop lever. On a .380 gun that is liable to make bullets touch the pawl and cause a premature lock-back. Browning solved the issue by not having any traditional ledge in the plastic. Instead, the top loop of the magazine spring pops out clear of the magazine body to activate the stop. This way the stop's pawl is always clear of the bullets.