Another nice feature about iTead is the 100% testing option.
I have had good experiences with their service so far. Only one order was messed up - I got 20 of a single design instead of 10 each of two designs. When I pointed it out to them, they re-ran the original order of the missing PCBs and included it in my next PCB shipment for free.
I too worry about the iMall transition. Not sure why it was needed, what it fixed. I have an order in production now, let's see what happens.
As far as shipping goes, the reason to use DHL in the USA vs. the USPS is the turn time in the customs warehouse. I've waited 3+ weeks for parts to clear the US customs when shipping with the USPS. DHL seems to have a greater interest in getting the parts delivered - 3-4 days total time from shipment in CN. Thus, I consolidate multiple PCB orders into one shipment and pay for the extra $20 to get the parts via DHL.