Using loops, such as logics loop browser, can be a treat if you have, for example, a nice drum pattern layed out, and you can use another drum loop on top or under that loop to add another character, or another dynamic to your drums.
I find that sometimes a nice simple loop can really dial in the rythhm of the drums you were looking for..
If the loops are eq'd filtere modulated and used creativly for the good of a piece of music then we are good to go.
But using some thin cold drum loop, with a corny synth loop and a cheesy string loop, that aint the shyt.