I started giving my son the bottle at 4 days old...mostly breast fed, but definitely gave at least a few bottles of breast milk everyday. And gave formula as well on occasion. I also gave him a large variety of bottles/nipples. avent, playtex, gerber, nuk, dr. brown wide and standard, etc...He never seemed to mind which bottle or content it was he was getting, but when he was 10/11 months old, he started to walk and discovered that the breast was not mobile and he weaned me at that point from breast feeding (which was sooner then I was ready for...easy wean process on him because he did it himself, but sad for momma)
So I'm not convinced about nipple confusion, etc... however, each child is very different and soon we will be having baby #2, so we'll see if this baby is as flexible when it comes to bottles, breast, etc...I hope to BF this one longer, so I might keep the bottle down to 1 or 2 max per 24 hour period, just so on those rare nights that I'm a COMPLETE ZOMBIE Daddy can take on a feeding.

Otherwise I'm a captive prisioner and no one can give me a break ever.
I think part of the problem is people don't introduce it soon enough because they are concerned about nipple confusion...they wait until 5 weeks or so and at that point the baby (IMHO) is used to a steady nipple and isn't as open to change as they might be in the very begining...hence the reason I opted to spice it up with various nipple sizes, bottles, breast, etc...