This topic is like beating a dead horse. At least one new thread a day about Synthetic oil.
Synthetic oil is obviously better, but the brand name does not matter. Some people religiously swear by Amsoil...Amsoil is no better than any other Walmart full syn oil(Was proven by lab). It is outrageously over priced and you can get just as good, if not better engine protection from any other synthetic oil at Walmart (Mobil1, Castrol, Quakerstate)and it is by far cheaper to do it. I personally wouldn't wait for 15k to do an oil change, I do mine every 3k or so. If you wait that long at least change the filter every 3-5k...But since your gonna be under the truck to change the filter might as well take the extra 5 minutes to change to oil. Only makes sense.
BEWARE OF THE AMSOIL MORMANS!!!