T90 is the one that I spend the most time with, among the three HPs I currently keep. Driven by the Hugo, compared with the Grado PS500, T90 has much larger soundstage and thus better instrument separation. I appreciate this a lot. Compared with the HD800, T90 is not as detailed, neutral as the HD800, and HD800 has even larger soundstage. But for POP and EDM (which I listen the most), T90 simply has a more vivid tone than the HD800, and thus is more fun to listen. Just my personal opinion, hope it helps.