Now that this thread has apparently hit a stride that is more scientifically based I think it is worthwhile to remind all concerned that nomenclature here is paramount. There is an extreme difference between Quantum Gravity theories and Loop Quantum Gravity theories, somewhat analagous to the boost that Ed Witten gave String theory with supersymmetry resulting in M Theory. In popular terms referring to them interchangeably is akin to equating Ron Howard with Ritchie Cunningham or even Opie.
It isn't that Quantum Gravity has just led directly to Loop Quantum Gravity after the former "hit a wall" in 2004, it's that the "crash" branched out into many theories, with some saying LQG being the most simple, elegant and well-developed. Ifo one hasn't the time to read complete books (which are often years getting to press, but are vastly more complete) it is at least worthwhile for wiki goers to be certain to view both
Quantum gravity - Wikipedia, the free encyclopedia
and
Loop quantum gravity - Wikipedia, the free encyclopedia
Even better see this:
be sure to use HQ if your comp supports it, definitely go fullscreen, possibly keep a hand on "brightness" control for reading projected text and don't miss parts 2 and 3. It's superb and points out the "non-perturbative" vs/ "perturbative" differences between the two and the considerable split that results in substantial progress in one of the few Background Independent theories in quest of understanding our Universe. Number geeks will not be disappointed but it is by no means above the heads of the math impaired.
It is said that Quantum Gravity replaces the Big Bang with the Big Bounce but Loop Quantum Gravity does not require it. So this thread goes on, soon to be "quantum leaped" by several new experiments and instruments as divers as LHC and numerous new space telescopes, some at LaGrange points, such as Herschel-Planck. This is a very exciting time!
