I breastfed and we were thrilled with the breastflow bottles. I used them exclusively in the early months (don't remember how long) and they don't have the "extra" parts. There are so many things to wash, and with breastfeeding you have the addition of all the pumping-related paraphanalia every time you generate a bottle's worth of milk. I would think all the bottles would generate a similar cleaning workload if you used bottles exclusively.
Once her bottle-use skills were firmly in place and she was in day care (so more pumping and more bottles) I used a combination of the Breast Flow and Avent. I liked them both equally well, and I didn't detect any difference on the baby's part. I didn't like the ones with the asymmetrical nipple. (Can't recall the brand.) My daughter didn't take them quite as well and you had to worry about getting the "right" side up. Which granted, is more of a problem when the baby starts holding the bottle him/herself.
But I hear all baby's are different. A friend of mine suggested we register for a variety of bottles. That way if your baby is picky, you will have options. And if you baby is indescriminant you can either choose based on your preference, or use them all!