Bluntly speaking as a male, not at all.

Now know this for a stone cold hard fact. There is a percentage of men that clearly this would be an issue but you can easily avoid that by not being attracted to that shallow of a person who is in to big boobs just because they are big.

I myself think that breasts are beautiful and are part of that woman. And when you are being intimate the pleasure is not lacking based on the size of the bra that came off! It's all good!