The biggest difference between Dawali Mediterranean Kitchen's perfectly acceptable Regular Falafel ($3.95) and the "house special" Classic Falafel ($4.95) is the addition of stuff. So with the tomato salad and tahini, you also get roasted vegetables like eggplant and cauliflower, along with a nice smear of hummus. These, plus a few squirts of the restaurant's hot sauce, are worthy additions and totally worth the dollar up-charge.
As with any falafel sandwich, all the extras would be worthless without a good falafel underneath, and Dawali luckily puts out a solid version. Featuring a crisp crust and a nice green interior, it's a good base. The only thing holding the sandwich back on this particular visit was a slightly stale and cold pita, a mistake that Dawali doesn't usually make.