Menu music has always been excellent since GT5 Prologue, no doubt about that. But outside of Daiki Kasho's brilliance and some of Nittoku inoue's work, their race music selection hasn't been as stellar since GT3. GT3 has the only good race soundtrack, IMO.
Sometimes, I wish they'd just ditch the licensed music if they can't pick them out well enough, and just go full on original. Like Driveclub did when it had Hybrid doing the soundtrack from the ground up. And it was good, actually.