I'm just stepping in, because my cousin is actually rep'd by this agency and has done very well. She is thrilled with it, and I see her promoted quite well. TBH every bookstore I enter her books are present OR even in the front. I hear the ladies at IG are terrific, and as for no-responses, from querying like a maniac I see it's just the nature of the business. We number in infinity and an agencies have a finite number of people and time.
Keep on trucking though, I just landed an agent, and thought I never would!