Personally I think there is a great mathematical beauty in String Theory, and a number of important advances in both mathematics and theoretical physics have emerged from the study of this model.
However, “it’s beautiful” is not a scientific argument, and no indicator as to its value as a valid model of quantum gravity. One of the main problems I see right now is this - String Theory doesn’t actually produce GR in the classical limit, it produces GR plus a large number of scalar fields. There is no evidence for any of these scalar particles in the real world, nor is there any known way to mathematically remove them from the theory. This is an awkward problem, and I don’t see it being discussed very often in the ST community. Furthermore, we don’t actually know whether or not ST is even capable of reproducing all the particles of the Standard Model (plus their interactions and symmetries) in a self-consistent manner.
My take on this is - String Theory certainly warrants further research, but it is at best unclear whether or not it can produce a workable model of quantum gravity. There are a lot of fundamental problems associated with this model, which would need addressing.