I would keep it. After a while they start to add up. I then use mine to purchase a nice coin or note I have been really wanting.
Nothing special that I can see but it's a fairly low number star note so if you don't need the $20.00 keep it.
It likely isn't worth much over face. I cash in my high runs once they get to an amount enough to purchase a coin. Sometimes my LCS will knock down the price when I pay in all star notes.
This is a cool site someone posted the other day. Plug in your notes serial # and see info on the "coolness" of it. http://www.coolnumbers.com/index.asp
I can't say whether to keep or spend. It's from a run of 3,200,000. It was printed at DC in January, 2011. And, no, it's not a low, cool or fancy serial number.