First, I cannot comment on the mail order service of Halalco because I have never used it. What I can tell you is that in the metro DC area Halalco has a very good reputation. Halalco has been around for seemingly forever and it has become a sort of one-stop-shop for area Muslims. As the name suggests, Halalco sells HALAL products; this means you can purchase meat (and other products) that you know are certified halal. The chicken and lamb are of particularly high quality and you would actually be hard pressed to find another grocery store, Muslim or non Muslim, that sells such delicious, high quality meat. The aisles are jammed with a variety of products and although the clientele is mainly Muslim, the product selection suggests that many non Muslims including Hindus and "regular" Americans feel welcome enough to browse the selection of exotic spices and Korma mixes. The book selection is huge and has titles covering every aspect of Islam from every perspective (Shia, mainstream, radical, etc). I find this variety refreshing. The customer service has always been about on par with what you find at any grocery store so I don’t have too many complaints. Overall a great place to shop.