i've never been an avid fan of drum loops, as i've always enjoyed programming drum and percussion parts. i use BFD, but it's not for everybody. it's not going to sound that great if you don't invest time on it. it's got great reviews too. it's a little heavy on the cpu though, and eats up RAM and your hard drive is going to get quite a workout from it. it fires 11 samples (24 bit samples) per hit.
....but after all the trouble, it's going to reward you with drum tracks that are frighteningly realistic.
you can change the personality of a single drum kit by simply manipulating the balance between room, overhead, and pzmmics, in relation to the direct mics.