I don't like it, I never have. I think the men that do this whistle at anything and it draws unwanted attention.
I suppose you're not being unreasonable if you like that sort of thing, OP, but it's awfully difficult for those of us who don't like it and don't find it in any way flattering. We don't seem to have the choice as women and I don't like that at all.
Comments with sincerity can be lovely - I was chatted up by an elderly man who complimented me on my turquoise swimsuit, saying how it perfectly matched my eyes (which are green)... oh well.
Lovely man anyway and I hope I made him smile as much as he made me smile.
I can walk past a dozen builders not working and not feel in the slightest like whistling at them. Why can't they get on with their work and do the same?
I think perhaps it comes down to having been whistled at and grabbed all the time from the age of 11 onwards. That should be against the law, I was a child, much as I looked older. Is that ok with some of the ladies here who enjoy such attention? What if it were your daughter? I ask because the men that do this have no respect and no discernment. They don't care how it makes a woman - or girl - feel. 
Thank goodness for the building site rules, long overdue and very welcome for many of us, I think.