For starters, Great Wall was bigger, much bigger than my local market, the size of a great big supermarket like Superfresh or Stop and Shop (or, indeed, McCaffrey's in West Windsor). Being bigger, it was also jammed with way more people. The checkout line moved surprisingly quickly, however. It was pretty overwhelming, though, and since the layout was different than the local market's, I probably missed some things. Most notably, the local market has specialty sections for Japanese, Korean, Thai, Vietnamese, Malaysian, Filipino and Indian food items, while Great Wall does not break these items out the same way (so, rather than looking for Japanese shoyu in the Japanese aisle, you need to find the Japanese section of the general "seasonings" aisle). It was kind of like visiting a parallel universe where nothing is quite where you expect it to be, but that's more a factor of how imprinted I am on the local market than Great Wall's fault. I also didn't notice any specifically Indian ingredients at Great Wall (such as Maya spices, which I'm used to seeing at the local Asian market, which is next door to a little Indian grocery store).
Digression: it turns out that that little Indian grocery store, Desi Corner, had its moment of blogging stardom in this post from John and Lisa Are Eating in South Jersey.
I'll need to go back during a less crowded time to explore in a more leisurely fashion, but I found some Lan Chi sauces (which the local market no longer stocks) and Mizkan honteri mirin (my latest attempt at satisfying my mirin cooking needs without buying aji-mirin or sugaring up some drinking sake). On the other hand, I found no yuzu juice, nor Shirakata-Denshiro Soten tea (and, although I got Lan Chi's Soy Bean Sauce with Chilli, their Barbecue Sauce was nowhere to be found). The lunch counter looked intriguing (it even had an eat-in section with seating), but that will have to wait for another visit. I picked up a couple of pounds of pork shoulder that was absurdly cheap and threw it into the freezer when I got home. I also got a big hunk of ginger root, some fresh mushrooms and some Bull-Dog Worcestershire sauce (since I've been thinking that it's about time to check out the Bull-Dog mystique: heck, you can even be their fan on Facebook!).
Also noted for future reference were Pho 99 (NJ SPICE review), in the same mall as Great Wall, and a little roadside burrito joint on the west side of Rt. 1 south of New Rd.
Here are some Yelp reviews (none by me) of the Asian markets mentioned in this post:
Great Wall in Franklin Park here.
Plainsboro Asian Food Market here.