I also noticed that IE11 (both Metro and Desktop), Chrome 32/33, and Firefox 26 on the SP2 all render gradients differently. Overall on the SP2 I would rate Firefox best, then Chrome, then IE (but all pale in comparison to anything on my desktop monitor).
For example on the Lagom black level page, Firefox on SP2 actually shows some grey on swatch #6, whereas IE and Chrome don't until swatch #14.
Similarly on the Lagom gradient banding page, Firefox grey gradients extend the furthest towards the edge. But Chrome seems to have the smoothest gradients.
On the Carldavis SmugMug test image, IE has very noticeable dithering on the brown background (!), whereas Firefox and Chrome are much smoother.