I have no idea which one has better glass but just looking at the features, the lrt has a a second focal plane reticle and the lrp is available with a first focal plane reticle. Throw in more zoom with probably similar level glass between them(someone correct me if I'm wrong) and I would get the lrp.
I have a mk4 lr/t sfp but I am hooked on ffp reticles thanks to my father in laws nightforce...