We use MAM bottles with DD2 (not the anyi-colic ones, too much hassel!) and she moved from slow flow teats to medium flow ones at 5 weeks. She still uses medium flow teats now. W have tried moving up to fast flow a few times but they were always way to fast and she would choke within a few second of putting the bottle in her mouth.
We started off using the MAM anti-colic bottles, but they were such a faff, and it was difficult to heat and cool a feed as water would leak into the bottles from the srew bottom, so we decided to switch to the regular MAM bottles as she loved the teat shape. We were very lucky that she wasnt a windy/colicky baby. With our new baby we will be using Dr Browns bottles as I have heard great things about them, and would rather minimise baby's wind from the ofset with also having to juggle looking after 2 other children! xxx