It's nice that Roti's is open until 8pm on weekdays so if you work in the loop and have to stay late at the office, you can grab dinner. Most fast food joints in the Loop don't stay open this late. So Roti's is good for that. But honestly, unless you're in a hurry or are trapped in the Loop and Roti's is your only option, skip this place. Their offerings are mediocre at best.
This Roti location is in the theatre district so if you're in the area b/c you're seeing a show, forget Roti's, catch a cab and head to Greek Town which is just across the river at Adams & Halsted (about a mile away). If you're vegetarian, go to any Greek restaurant and order the vegetarian moussaka for some melt in your mouth deliciousness you won't soon forget. If you're vegan, go to Karen's on Green. Karen's on Green is an upscale vegan restaurant (not a Greek restaurant) which happens to be located in Greek Town.
If you're new to town, tell the cabbie to take you to Adams & Halsted. That's the middle of Greek Town. Halsted is restaurant row. You can walk up and down Halsted, check out the restaurants and menus and find one you like.