I can't say that Jack's Deli is my favorite place, but it's pretty good and it's consistent (at least in my experience, but hey, isn't that what Yelp is all about?). One of my best friends lives by here, and he swears by their Reuben. If he is feeling down, this place is where I take him.
Typically we got there for lunch, and on Friday we both needed something tasty so we hit up Jack's. J got the Reuben (of course). The server usually brings their house made pickles, but I can't comment on them as (gasp!) I despise pickles. However, my other friends usually ask for seconds, so they must not be awful. The Reuben is a nicely sized sandwich, and always hits the spot for him. I'm a huge fan of their potato knish. Nah, it's not a culinary masterpiece or anything, but it's good. It's truly some of my favorite comfort food - give me a potato knish with gravy and a bowl of soup. Their Matzo balls are giant, and the broth is tasty. When I get the Matzo ball soup (a cup comes with one ball), you literally get a Matzo ball and broth. No carrots or any of that stuff you may typically find. However, I find it is really tasty without.
I love their lox - I had out of town guests and I had them bring bagels (they were travelling from New York, and sorry Cleveland Bagel Co, I still prefer New York!) so I picked up some lox from Jack's. They loved it! I haven't tried out their deli for anything else, but they seem busy.