A little background
Daughter #1 was a voracious nurser. I pumped while at work and she willingly took any bottle given to her at daycare. Daughter #2 was a weak nurser at birth (likely due to her then-unknown growth disorder) but improved. However, after 12 weeks at home with mom, she developed some serious nipple confusion when she took a bottle at daycare. She didn't take to the bottle and she screamed every night at feeding time. I would take her to a dark room and try to feed her for hours. Usually both of us would end up crying. Son #1 is pretty much irrelevant to this discussion because he has the pleasure of mom staying home with him 24/7.
After a lot of research I made some important discoveries. The Gerber nuk orthodontic bottles and pacifiers teach babies to use a shallow suck that is not good for breastfeeding.
A good breastfeeding bottle mimics the natural shape of a mother. We discovered The First Years Breastflow bottles and Pacifiers.
After we switched Daughter #2 to the Breastflow bottles, life was easier but not perfect. I think if we had started with these bottles, she would have done much better. I ended up working my full time job in 2 1/2 days a week and staying home the rest of the week with the kids. At 9 months we moved to Minnesota and I entirely work from home.
If you have a new baby, just buy one or two of the bottles you think you would like to use and try them out. If that bottle does not work, then go back to the store and try a different one. Every baby is different, even within your own family.
If you have low milk supply and are trying to pump, I found these Milkies Milk Savers to be very useful. You place them on the side you're not nursing on while you're nursing and they collect the milk that drips. I was able to freeze a lot of milk before I went back to work by using these every time I nursed.
Feel free to ask questions!