It does look a bit long in the sleeves. I'd size down one. Fyr, I'm 5'10" 158, 38R, and own the Monitor Down in S.
As for the earlier comments about puffiness, I can layer a cardigan underneath and it still looks pretty sleek, imo. Have gotten plenty of compliments on it already. I never mention it's Veilance unless people specifically ask--bc of the pricing it seems obnoxious to say.