It's going to depend a lot on the specific cultivar....some are just a lot more colorful than others. It also depends a bit on how many sterile florets they produce. Less sterile florets = less color.

I just snagged a 'Lady in Red' start from a gardening buddy simply because I preferred the softer, almost smoky gray-blue color of the lacecaps in our acidic soil. IMO, one can have too much intense blue ;-))