Tokina has aimed for low distortion, uniform sharpness, low aberrations, flat-field and very smooth bokeh with their new 24-70 f/2.8 lens for full frame. Looking forward to seeing how it performs in further testing but the samples here are a good start. no swirly bokeh!
www.kenko-tokina.co.jp/tokina/atx24-70.html
www.kenko-tokina.co.jp/tokina/atx24-70.html