I think Luke's is just so-so.
A group of us Chicago transplants at the office made the trek to Luke's for a nice Friday lunch. I did the combo sandwich and I was a bit surprised that for the price fries did not accompany the sandwich. The giardinera (sp?!?!) was also nothing like I was used to, and frankly disappointing. It was a bit greasy too.
IMHO, Chicago Gyros does a much better job.