I have been to Which Wich plenty of times, it is in my top 5 of sandwich shops. They have awesome flavor to their subs. My favorite is their buffalo chicken! They have so many different choices.
The shop is unique in how you order, but I love it. You pick a bag, mark what you want on your sandwich and they make it. They call your name when it is ready.
The only con: it can get busy fast, so the tables are taken and there is not much standing room without thinking you are in the way. Grab a table quick!
Also get the club card, you get a free sandwich after buying so many.
I hope they open one on the south side soon!