I grew up a couple of blocks away from the original Belly's. I'm not sure what I was expecting but I was disappointed. The first thing I noticed were the prices, $8.25 for a bacon combo. Maybe I was expecting the prices from my childhood. The bread seemed very doughy/fluffy, which I don't remember from the original. Definitely better than other sub shops but nothing to write home about.
I was surprised at the cash only thing as well. At least get a square reader for the iPad and take credit cards.
If you are going to open a second location try to staff it with unique people. My buddies and I used to hit the original after a night at the bar. Hermes the original owner would stay open until 4AM just for us kids and always smile and take us with a grain of salt. I don't think he would be happy with this store.