I was fine with the m50s, but again I also had the luxury of auditioning my friend's for a week before i ended up buying them. (the summer guide or spring guide last year really helped me feel better about it). and I didn't notice anything harsh, but i will say........the soundstage isn't grand/big like open counterparts. The gap between the m50 and ad900x[ath open headphone) in terms of soundstage is insane.
It was a great entry level headphone for me, but at $99 it was a great deal i thought.
that headphone got me into this mess (where your wallet hates you), but I also am happy for it. I've gone onto 3 other headphones since then. and still am only in "mid-fi" territory.