First off, I should say that my review is probably biased: I've been going to Broadview Espresso (Sumach Espresso's older sibling) regularly for a couple of years. With that in mind, SE hits all the same high notes (delicious drinks, friendly relaxed staff and inviting atmosphere) with the added bonus of resting inside a beautifully designed space and offering more robust food options. I didn't have a chance to try a sandwich, but owner Mike Cullen has a passion for cooking and I wouldn't be surprised if they were great. Not that most sandwiches require any cooking.
Try Sumach Espresso.