I own the AQ Niagra 1200, too. I have no issues with it.
I also owned the Equi+Core 1800- a very early version.
It worked well with my equipment. To be honest, I did not detect a significant difference- but, I try not to get too anal about these things. When they make a difference, I hear it, but if it trends to the subtle, I just call a spade a spade.
The Deep Core is a YMMV piece of equipment. If your current is of less than decent, then it could make a difference. -And, yes I owned a pair-both sold.
One reason I moved to AQ is that the Core Power equipment seemed more like a bunch of 'better quality' outlets put in a box with more conventional parts/wires.
The new AQ stuff is really quite amazing (to me, at least). Garth is putting out some very nice cables. The Niagra 1200 is part of that-perhaps it doesn't have all the upgrades that come with going up the line (3000-7000), but it does do the job nicely.
Bob