I haven't heard the Circle Surround 2 version.... just the older 2 output basic units.
I was unimpressed with the CS 1 output when it drove but 2 speakers and was not fed through my Vario-Matrix decoder. It was okay but nothing to shout from the rooftops about.
But, when those 2 CS outputs were fed into the 9001 where the VM could work upon the output of the CS unit, wondrous aural delights reached my ears. And, the controls on the CS units allowed much more "tailoring" of the sound that the controls of the 9001.
I suppose that the CS output sorta' "primes the pump" of the VM decoder. I have experimented over the years feeding the outputs of various processers and decoders into the input of the 9001 to see what would happen. Until I tried the CS all earlier experiments were failures. Then, the CS experiment occurred.
There is something different about that early CS unit's output that the VM revels in. Whether I used an encoded matrix or a stero source, the VM created an excellent sound field that could be fine-tuned to a large extent vis the 2 CS controls affecting its output.
Of course, people hear differently but, to my ears, the combination of that early CS output fed into the VM has given me the best surround sound I have experienced so far. Previously, everything I played went through the VM. Now, everything goes through my "dynamic duo."
In another post I mentioned the differences found between my Nureality CS unit and my recently acquired Hughes AK-500 2 output CS unit. Of the two, the Nureality produces an exciting liver quiverin' output. For reasons I can not determine, the Hughes unit, though similar in output, is lacking something that leads to aural ecstacy. If I had started off with the Hughes unit I would have shunned the early CS as not being enough of an improvement to bother with. But, since my Nureality unit does give the VM a signal it revels in working with I am convinced that, for me, unless something better comes along, I will travel the trail of my CS / VM combination.