Thought I'll update this threat with my poison.

Yup, got the 8 GB 30 MB/s card in the end. Unfortunately, my informal shooting timings were disappointing. It was marginally faster compared with my existing Lexar Platinum II 4 GB at continuous 4.5 fps shooting, and it takes around a second faster to display the 10 photos I took (I switched to MF on the body so that it doesn't need to slow down for AF). Copying from the card to my laptop took around a second faster too for "Xtremy" using the Lexar USB 2.0 SDHC reader. If it matters, "Xtremy" was tested as it-is out of the box while "Lexy" card had about 2.5 GB of free space only.
I guess the difference will only be more apparent when you're shooting a lot more photos continuously. What else is there to dislike about "Xtremy"? The use of those hard plastic kind of packaging inside the box is hard to open, and contrary to *my* belief no reader was bundled, unlike my Lexar purchase.

In short, yeah, I got suckered into the whole Extreme brand quality. Now's hoping that the card will really live up to its name when I'm overseas for an extended period of time early next year... the reason why I decided to give it a shot was that my "Lexy" had died twice in my D90 (I suspect due to bad sectors) although it was working fine in my Ricoh GX100 for the past couple of months.