All multigrain is (compared to white) is it contains flour made with something other than wheat. It has to be whole wheat or whole grain if you want to get more fiber out of it (though even with that, as with all things, you'll see the nutritional panel of different brands vary)
That said, if you're not used to eating whole wheat or whole grain breads, it's a way to ease yourself into the taste of it. Which is why I suggested it as a sandwich option, especially if whole wheat isn't offered. Not sure what Subway has.
Admittedly I don't eat a ton of bread but the stuff I usually buy is Dave's Killer Bread "21 Whole Grains and Seeds". Nutrition panel here: http://www.daveskillerbread.com/21-whole-grains-and-seeds