Is the yellow shift you mentioned what I can see on the viewing angles section of the TFTCentral review?
If so, the Dell seems to perform significantly better in that respect :
No doubt the TN gradient is still there and always will, but so far those IPS are plagued with significant temperature shift on top of higher than normal IPS glow, and often horrendous BLB. Pick your poison.
Another thing I'd like to point out from the TFTcentral reviews is panel uniformity :
(XG270HU, PG278Q and XL2730Z perform almost identically to XG270HU in both the viewing angle and uniformity departments)
You can see the Dell performs much better uniformity wise. Although the averages are similar, the max difference is much lower on the Dell. Maybe that's a coindidence and TFTCentral got a REALLY good sample of the Dell... or maybe Asus and Acer buy lower grade panels to increase profit margins, which would explain why many people are happy with their S2716DG in comparison to the PG278Q.