You can do both.
Say you got a 2 bar loop that has drums on it. SAmple it, chop it up.
lay down the sample anyway you want. roll off the low end below 80 or so. Then play with the EQ to find a good balance of the sample you want, without taking out all the low end.
chop your drums, lay your own pattern over it. if you freak it right, you can hear the orig. drums from the loop, but as ghost notes, with your own drums driving the track.
if you freak it rite it will sound dope.