Hi,
I am running a simpler 7.1 setup with Wharfedale DX-1 speakers (7 nos) and the subwoofer with Marantz SR6006. I was very thrilled initially and heard the effects steer through the room and was pretty happy with the set up.
However with 5.1 sources, it is pretty useless and the surround effects even in 5.1 set up are not that mind blowing all the time.
This experience boils down to several things
1. I am not a fan of 3D technology, especially with passive/active glasses. My TV supports 3D and I watched some 3D movies, but the effort is not worth it. I feel the same (if not to the same magnitude) about 7.1 set ups. You need two extra speakers, cabling, an amp capable of doing this and in the end it might just fizzle out
2. Room & set up - May be my set up is not done the right way and I am missing the point.
I had never done any demo of properly set up 7.1 set up. Since my amp is capable and the additional two speakers were not too pricey as well as I used standard copper wire, I went with the set up of 7.1
But, if I have to advice, I suggest you take a proper thorough demo of 5.1 / 7.1 set up. Also, during the demo try to use the content which are not good examples of surround effects. Good examples will blow your expectations high, but IMO all 5.1 material does not have same amount of surround effect awesomeness. Also try to experience the phantom effects that can be simulated by the receiver for two channel content.
As, I said surround effects might not have the pulling potential to all audience. And there are more factors like Room, Set up etc, as mentioned earlier by other members, play a significant role.