1. When does one introduce the sippy cup?- I started introducing it at 6 months, and he was on the cup exclusively by 10 months.
2. Is it better than a bottle?- Orally, yes; but, of course, only for a certain amount of time. A sippy cup for too long can be just as harmful as a bottle for too long. Or a pacifier...
3. When do you go to a cup/ straw?- When they learn to drink from a straw. That can range for some kids. Some kids can drink from a straw at 13 months, and some not until they're 2. My son turned 18 months at the end of February, and that's when I was finally able to teach him to drink from a straw. I'm pretty sure I could've gotten him to drink from a straw sooner though, if I'd done before what I ended up doing to teach him. Once I finally figured out what would get him to learn, he literally did it after the first try.
4. Do you continue offering bottles?- At your baby's age, yes. Once you move exclusively to cups, why would you go back to a bottle?
5. At some point, I guess the bottles stop. How do you do that?- I just didn't offer it anymore, and he didn't mind. As long as he was getting milk and/or water from something, he didn't really care.
6. Are some cups better than others?- Yes. Some are actually rated by and approved by some American Academy of Pediatric Dentistry or something like that. The brand that I've found to be the best, and I absolutely LOVE, is Tommee Tippee.
7. Are there any that are spill/ leak proof?- Yep, Tommee Tippee. They have a website that you can go to and see their different products.
Edited to add: I forgot to mention that my son was largely breastfed as well. He was breastfed exclusively until around 5 months old. I went back to work when he was 4 months old, and then even w/ pumping, my supply started really decreasing. So, at 5 months, I still pumped what I could and then supplemented with Enfamil Premium Lipil. This went fine up until he was 7 months and his dad and I had to go to Jamaica. I knew that would be the end of breastfeeding altogether. Although I could've pumped the whole time I was away, it's just not the same as actually having the baby there, and just like I thought, my supply dropped down to almost nothing :-( So, he was on Enfamil from 7 months until about 11 months when I started mixing it w/ whole milk and preparing him for the 1 yr old transition. I say all this to say that because he was breastfed exclusively for the first 4 months, it was HELL trying to find a bottle he would take. I tried almost every brand, and the only one he ended up taking was the Breast Flow bottles. So, I was very pleased and surprised when he took the sippy cup so easily.