I might as well ask the same question. I've always flown J, and have four flights scheduled on the A380, MAN-DXB-NRT and KUL-DXB-MAN and have the option of upgrading from J to F on a couple of flights using my accrued miles.

Now considering I'm one of those that, erm, "likes to stand up during the fight" if you catch my drift, is upgrading to F really going to be worth it considering I'll be upstairs but down the back of the plane?

^