Well, I have had both the SoundSticks and the Creatures, and now have a set of Logitech z5500's, although I'm looking to upgrade to Klipsch Ultra 5.1's.
In any case, I'm not going to get into full reviews here, but the Creatures are very nice and compact, and put out a TON of sound for what they are. However, if you're looking for something from JBL, check out the 4.1 Invaders. They are speakers with dual (creature) drivers in each speaker, and put out EXCELLENT sound. Sound quality wise I would put those above the Creatures and Soundsticks, because it creates a very full and encompassing sound.
The soundsticks are crystal clear (in the high end), and the sub puts out a very nice and satisfying low end sound-- worth the price difference between them and the Creatures? Yes-- but it is debatable.
Personally I think you would be happy with either of them, it's really a matter of what you want.
Soundsticks
Pro - Look nice, 4 drivers in each speaker, full, room filling sound. Clear sound quality
Cons - No 'off' button, the mids can get a little muddled.
Creatures
Pros - Look nice, compact, full sound for what they are. Good mid and high end.
Cons - No 'off' button, lacking on the low end a bit.
Invaders
Pros - Very full and encompassing sound, crystal clear mids, highs, punchy lows.
Cons - No 'off' button, not as visually pleasing as the others.
Not trying to turn this into something that it isn't, but I since I've upgraded, I still have my sets of JBL Invaders, as well as HK SoundSticks II just sitting in storage. PM me if you need more information, or more advice.
Good luck!