No, I have to disagree with you, macaddict. People routinely buy inferior generic RAM for their Macs without problem. Mushkin is name brand RAM. There is nothing inherently superior about Crucial in comparison to any other name brand supplier - the thing Crucial has going for it is popularity. Now the only question I have about Mushkin is, they have a separate Mac RAM section on their site under the label "Graphite." I don't know why they've made this distinction, but I assume it was made by their marketing department. I'm going to call Mushkin to find out why, and I'll edit my post when I find out more information. But otherwise, the Mushkin RAM listed by newegg looks to be in spec for the G5, and it's sold in pairs, which seems to indicate G5 suitability.
Edit: I could not get a hold of anyone at Mushkin over the phone. so hopefully they'll respond to my email in a timely fashion.