[Solved] P8Z68-V PRO with Mushkin 996782

Most of the newer boards will work with about any RAM you throw at them (within spec, of course). Honestly, I consult the QVL as a start point and go from there. When I haven't been able to find something exactly from the QVL, I've always gone with something with similar specs and never had a problem with it not working unless there was a bad module in a kit.

Mushkin, OCZ, G-Skill, and Kingston will generally give you a good value. RAM is darned near a commodity anymore with most companies pumping out good-quality modules.

Mushkin probably recommended this other RAM module model because, even though the latency is different, they've probably already tested this RAM on that board.

If you're looking at different RAM as an alternative, just consult with the QVL.

Additionally, when I buy RAM, I like to buy it locally, especially if you have a microcenter nearby. You can usually find something close to mail order prices there.
I've had bad modules in the past through mail order and that usually adds a week or more to your build time. Also, if you buy locally, you can just walk in and exchange it if it doesn't work. Not everyone has this luxury, but if you do, take advantage of it.