Of course
Used correctly, any product from Auralex will improve the sound of your room. I don't have testimonial of actually using the Roominator kit, but I do have testimonial of using Auralex foam, and it's really good.
Just keep in mind the foam included in the Roominator will not sound proof your room, that's not what you're after with foam, what it will do is make your room sound better by keeping reflections and flutter echo down, and will help to eliminate room modes. You may know this already, EMU4XT, but I say this for the people who do not know this already. I just like making that clear.
Later,
-Brian