If you changed your oil on time there shouldn't be any deposits in your engine!
Advantages to running synthetic are better mileage, less wear and tear, and increased change intervals. If you figure it out, running synthetic costs the same in the long run, but you are laying under the truck a lot less. I drive a lot, so thats important to me, plus the increased protection when working your motor hard is good too! (I tow a lot as well)