Finally had the chance to try the famed Jia Jia. As advertised the XLB was amongst the best I have tasted. Flavorful soup and thin wraps. But how do they compare with Ding Tai Fung? We have also had the chance to go to DTF this trip (about the 4th time we tried DTF at different cities). And the verdict is, the two places serve very comparable tasting XLB. So taste-wise we judge them to be a tie. Price-wise of course there is no comparison, as DTF is 4 times that of Jia Jia. However, at the end we'd still prefer DTF for the overall ambience, the availability of a full restaurants dishes, and the service. DTF Shanghai also has the mini XLB every day. This is only available on weekends at other DTF locations.
On a side note, we also tried Yang's fried dumplings across the street from Jia Jia. Since we had 4 trays of XLB from Jia Jia we didn't have much room left for Yang's, which was a mistake. This was the best fried dumplings we've ever had. Next time we'll definitely be back just for the fried dumplings.