i think the drag and drop drummer is more for working with preconstructed loops(???), whereas Fruity Loops can be used to construct your own loops plus put them together.....
ive heard things done with the Drag n Drop and they sounded pretty good...I use FL myself.....
I'm a newbie, but I have used a drum loop app called hammerhead rhythm station, which is really easy to use for simple loops. If you're just looking to goof around, this is one to look at.