Which is more creative?  If I use Groove monkee  DrumLoops or if I use Real band, Biab loops.  Are there significant differences in the variety of loops created from each?  Is Biab less flexible than Groove Monkee 's MegaPack?  I have both and love both programs; I'm just not sure which is the quicker method.  PG has a style maker but it is not set up to tell you which is an intro, verse, chorus ect.  So you have to do some listening to figure out what a style is good for and I don't have enough experience to call that judgement.  

Barring real drums, I love Jamstix b/c you don't just pick through prerecorded patterns trying to find the right one that fits.

Instead, you pick a style and a drummer and it can generate a part in real time like a real drummer. You can then use it as is or use the various controls to push different elements in one direction or another. Or you can even edit the part as heavy handed as you wish.

I would say that they are two very different approaches.
 
I see Band In A Box as a useful sketch pad to create a guide arrangement of a song. The range of styles means that with some patience I can usually get something that feels similar to what I am aiming for in the final mix. This lets me work on tempo and song structure in a flexible way by simply entering some chords. I will then export some of the tracks, typically Drums, Bass and Piano, and use them as a sort of super metronome for my programming and recording. Some of the Drums, Bass and Piano may survive but I will have reworked it. Personally I only use the Midi from BIAB.
 
I have limited experience of Groove Monkey but have used other similar products and they are good for building blocks. The ones that I have used tend to be more authentic than those that BIAB offers and usually offer better dynamics. Again I tend to prefer MIDI over Audio as this gives greater flexibility. Putting together a rough arrangement is a bit more effort than BIAB but the results in my experience are better.
 
I would add though that if you're using MIDI then it does not have to be a choice, you could sketch it BIAB and then enhance the results by replacing some or all of the track using Groove Monkey content. As some of the Audio in BIAB has a Midi equivalent you could possibly do this with Audio if you have single hits for the Groove Monkey loops so you could recreate the BIAB drum loop with the Groove Monkey sounds.
 
There is also the approach suggested by Byron of using different tool altogether.
 
A lot depends on how you like to work though. BIAB helps me because I tend to be impatient about getting a feel for the overall arrangement and like to play around with the chords and structure before I get too much into the detail. If you are more patient and are looking to create something that is more precise then BIAB I think will frustrate you because there is no guarantee that it will play the same thing twice.
 

I used Groove Monkey loops extensively back in the day, but now use BiaB exclusively for drums.  It is definitely quicker for me to get the sound I'm looking for.  But Groove Monkey loops are very fine indeed and have quite a bit more variety, to my ears.  I've also used Jamstix, and it is a very cool program, probably even more so for a real drummer, or someone who knows drums really well.  But that's not me.  :)