I like them too, but they really seem to be on the decline, at least here in LA. The good trucks that have always had long lines (Kogi, Border Grill, Grilled Cheese, Grill 'em All, etc.) are still going strong, but a lot of the others have closed up shop. Frankly, a lot of the others were just plain bad. But many of the truck lots are gone also, and some trucks have morphed into restaurants, reduced their fleets, or just disappeared altogether. This business seems to be maturing.
I love food trucks and there are still a good amount of them in NYC. They hold a food truck rally once a month in Brooklyn in Prospect Park where around 10 trucks show up. Lots of good choices! Grill 'Em All did a weekend visit to NYC after they won the Great Food Truck Race and we went to try them out 2 of the days. Definitely some interesting combos and tasty burgers but I am guessing things run much smoother from their truck opposed to when they takeover a restaurant's kitchen for a shift.