my ds was really easy. At 6 months we introduced it...mostly that meant he played with it during feedings. I never put anything that was not formula or milk into a bottle. By 12 months he had only a "good morning bottle" and everything else was in a sippy. On the morning of his 14th mo. bday I gave him a sippy for his morning milk...and he was fine, so I threw the bottles out. I think because we did it gradually, he was comfortable with the transition. My son is a thirsty little guy, so after about 8 months I could not use the little stoppers b/c he got frustrated and would throw the cup across the room. They are messy in the beginning....but it is so worth it. I would rather clean up little spills here and there than wash so many bottles everyday!
