It might be worth it. You will earn (at most) 37,500 more RDM and be *G and and have access to *G lounges if there are lounges where you travel international. You will be ahead of 2P's for upgrades, but still have a lot of competition. It will not help you with EQM for 2009.

You might might also use the $800 to buy a trip to europe or alaska and earn about 10,000 EQM and 12,500 RDM. (YMMV).