Go with the omen, I gave my friends a good testing, and I liked the feel more than an impy. That and when you compare the two, they both come with two of the best regs out there, but the omen is ready to rip out of the box, has a delrin bolt, adjustable trigger, etc. and for the impulse to stand up to the omen, you'd have to get a vision eye, a new trigger, a new bolt and setup.
I went with the omen, and I don't have second thoughts, a good buy all in all
BTW if you want a good price on an omen talk to Shadrach, he sells the new black trigged ones for 380 NIB, I've got a deposit on one from him right now