There are several very cool results from String/M-theory, but nothing that can be fully understood without the mathematics. But a theory that fully explains all interactions, including matter fields, with supersymmetry and supergravity arising naturally from it, an explanation of the heirarchy problem, and use of perturbation theory and renormalization for gravitons which are generally non-renormalizable, is interesting.

Loop Quantum gravity is interesting too, especially for its background independence, but it will never explain matter fields, and the semiclassical sector is currently lacking. By contrast, string theory has a natural extension to classical general relativity.