I love online undie shopping and do it a lot. But this is because my size (was 32A, now 34B) means that you're stuck with ugly, plain bras if you don't. Yes, some don't fit too well (2-3 of my 30 or so bras - when I found nice ones I got a bit obsessive after years of plain), but most do and I now know which brands to get! I love wearing nice underwear that matches so, for me, on-line is the way to go. Breaastfeeding-wise, it has been a lifesaver as I can't find bras my size in the shops and my 6 breastfeeding bras fit beautifully.