I got to know Soul Snare in one of the worst ways possible. Long story short, I found myself on the other end of it during a Commander game, and consequently had my momentum halted for several turns. You really don't want to attack into this thing. You also can't counter its removal effect once it hits the board (unless you're playing Stifle in a Commander deck for some odd reason). Oh, it also exiles creatures. In my opinion, Soul Snare is a solid defensive tool and a strong, reactive removal spell. It will buy you a few turns, and deal with threats when needed. And hey, who says we need to limit Soul Snare to Commander games? 

I know I do.