The Lower East Side is one of the best parts of Manhattan to stay if you're visiting New York. It gives you incredibly easy access to all parts of the city (right by major transit lines) and is equidistant from Brooklyn and Central Park alike. Umut & Deniz's place is also on a wonderful street. Ludlow is right around the corner (or on the same street) as a ton of great bars, cafes, and restaurants. There's a Whole Foods a couple of blocks away so you can stock up on snacks or big water jugs. Access to F, J, Z, and other subway lines literally 2-3 minutes away (walking). You can definitely walk around the neighborhood after midnight and feel super safe (though this applies to most of Manhattan).
Things to expect? You'll be sharing the apartment with another guest (or guests). There are two bedrooms. Your room will have a lock on the door for security and privacy. There's only one bathroom, so plan on sharing it. There's a living room with a comfy couch, small eating table, and kitchen that's stocked with plenty of utensils, pans, and other cooking tools. Cozy, charming, and quintessentially New York.
Umut replies quickly and is super friendly and accommodating.
10/10 would recommend!