SUBWAY VS KOSHER DELIGHT

Question

Dear Rabbi Abadi, I am a close follower of your Q&A forum and find it very informative and enlightening. I have a question for you which I hope you will answer for me. I work in Manhattan, right across the street from a Subway restaurant, and around the corner from the local Kosher Delight eatery. Does it make any difference at all "halachically or otherwise" whether I order a tuna salad sandwich at Subway or at Kosher Delight. In other words should I feel comfortable eating at Subway, given the proximatey of the kosher restaurant? Thank you for your response. D Arielson