The Lower East Side apartments for sale at One Manhattan Square have plenty of perks for residents: a perch on the East River waterfront that affords them stunning views, a choice of two finish palettes in each home’s state-of-the-art kitchen, and 100,000 square feet of amenities, including a screening room, top-of-the-line fitness center, and spa, just to name a few. The building is also one of the city’s last to offer a 421-a tax exemption for its residents.