Compared to scepter of summoning, this seems pretty weak...
It's basically the same cost as scepter except:
1) It costs recruits instead of gems (and I think recruits are generally more coveted, especially in a brigand deck)
2) It raises your opponent's tower by 15 (!)
3) It gives you a rare from your opponent's deck instead of your own, which is definitely not a good thing in general.