Impulse > BKO in my opinion, but their prices are kind of in different places, so it may not be the best comparison. A Bushmaster would probably be better competition for the Impulse. They are both about the same price. Most would probably tell you that the Bushy is better though.
Get a hold of a Bushy, and an Imp. Pick which one you think feels better to you, that will help you with your overall decision.
Ive gotta go with the bko. Last i checked which its been awhile, the imps were around $425 for a stock gun. The bko(new ones) Are around $350 with antichop eyes. With the extra money, buying a chaos chip, maybe reg or a barrel kit. I would say it would be better than the imps.