I wonder if there is anyone who has actually purchased a brand of bottle and used it without drama.
Yep, we did! We used Avent from around 2.5-3 weeks of age and had no dramas at all. We had loads of feeding and weight gain issues so DD was taking EBM top ups from that point. Not an issue whatsoever.

We've recently changed to Tommee Tippee bottles though as I wanted to get all BPA free bottles and they were loads cheaper than Avent ..... and very cute with brightly colured animals on them, lol. DD LOVES them (purely for the animals!) and had no issues with the change at all despite the bottles and teats, in particular, being very different. Clearly I have a bottle addict on my hands