You can turn the umbrella around and shoot through it to get a bit more of a soft box look. You can adjust how close the umbrella is to the light shining through it.
The good thing about a soft box is that you can keep the light off the background better.
Of course with an umbrella you can always put a large card up on a stand to block the light from going to the background.
I will often use a soft box to light the subject and an umbrella to light the background, but then you need to deal with the light spilling from the umbrella onto the subject.. which can also be used to your advantage.