defrag programs

Hello I have been looking at defrag programs ,and have found a 50% off  offer on UltimateDefrag 4 as I also do a lot of flight simming I like to keep my hard drives as tidy as poss ,has anybody had any exp with this program good or bad  ,any help gratefully received,(I have enclosed link hope no one minds)

peter

http://www.pcaviator.com/store/product.php?productid=19462