New toys and Softbox or Umbrella?

[Defy]

Since I got my 70-200 2.8 i have had 2 close calls with my sunpack tripod so today i finally bit the bullet and got (hopefully) my last tripod!

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I went with the Manfrotto 055xproB and the 488rc2 head. So far just dorking around with it today i love it! i paid about 300ish plus taxes (i know i could have got it cheaper online but i like supporting my local shop).

I also picked up a little softbox speed light kit and an umbrella to play with but now i have a question? What is the big difference with shooting through an umbrella or using a little softbox(no baffles and almost the same diameter)