yea its definitely worth it. my low beams are brighter than my old high beams were. theyre just about as easy as switching out a headlight except you have to secure the ballast to the truck somehow (i used self tapping screws)
http://www.f150forum.com/members/jon_to-27078/
^ that guy has been selling quite a few sets to people on the forum here and usually pretty cheap but again ebay has sets for like $30 but theres no warranty.
i bought my kit from a guy on here who was selling his. they had chinese writing and crap on the box but theyve worked for 2 years now without burning out. take a look at a few other peoples trucks with different colored hids. the 6000k i have are brighter than the 8000k but the 8000k is bluer. the higher the number the darker shade of blue