My sound blaster X4 arrived safe and sound and is working as expected. Feels like a quality piece of kit and it's got a ton of bells and whistles that I'll never use, but most importantly it's got standard 7.1 audio jacks so that I'm not cluttering up the front of my case with the rear speaker plug.
Unfortunately, needing (wanting) to grab one of these to overcome the 2 jack rear panel on this motherboard effectively turned an already expensive $630 motherboard purchase into an $800 (pre-tax) one. Really can't say I'm a fan of the current onboard audio trend, and really think that at these kinds of prices they should have at least provided a (low and high profile) breakout rear slot cover to make up for the lack of rear ports.