Will you hear $600 worth of better HT listening experience? Whether it is worth the extra $600 or not is up to you.
I will give you an example of one of my experiences.
I was watching Master and Commander for the 10th time at an audio boutique store one afternoon. It was the first time I was auditioning good speakers. While watching the movie (it was a scene where they are down inside the ship) I heard something, and couldn't figure out what it was. I was looking around the room to see if someone else had come inside the auditioning room. There was no one there. I couldn't figure out what I just heard. I played the scene again, and again heard the sound. It was the sound of people walking around on the top deck of the wooden ship. I was like WTF. I had watched that movie time and time again and never noticed that effect for the movie.
Good speakers will have better detail, and clarity. As you go up in quality, speakers will sound better. But that also comes with a price.
Will you have a good experience with the SVS system? Yes
Will you have a better experience with the Ushers? I will leave that for you to decide.