I'd say fairly similar; both are slim in the thighs/seat. HY pants come with unfinished hems, while SS usually comes finished. I was a 36 in HY, a 36L in SS Soho, and a 34 in Brooks Brothers Madison (traditional fit).
thanks. i have fairly muscular thighs and legs and i had to go up to 34 from 32 in SS soho pants to get the fit that i wanted so i guess i'll have to do the same thing with HY