Living in the area, I do enjoy Sultan's every now and then...but their falafel....not so much. As many have already mentioned, it's too crunchy and way too dry. I think the problem is that they don't fry them on a per-order basis. They just make a bunch, and let them sit there; sometimes serving them cold.
As a side note, their shawarma is great...very tender.
For falafel in Bucktown/WP, Babylon is my pick. Lite and crispy on the outside, warm and moist on the inside. They take forever to prepare orders, so call ahead...or just grab a six pack at Polonia(North and Damen, which as of last night, has Dogfish 120 minute

) and enjoy the wait. While you're there, try the lentil soup.
Now I understand that Sultan's is cheap and fast, but if you can spare an extra 50 cents and ten minutes, then do yourself a favor and hit up Babylon for your falafel fix.
Babylon Eatery
2023 N Damen Ave
Chicago, IL
(773) 342-7482
"We eat slowly and with gusto." - Paul Bäumer in AQOTWF