Have stayed at tons of Marriott properties in Manhattan, I've been at all of the below within the past 12 months:
Essex House is my favorite. Lovely location, excellent service, beautiful accommodations.
The Lexington is conveniently located and budget friendly. Standard rooms are very no-frills, but are clean and comfortable.
AC Hotel Times Square is my go-to if I'm seeing multiple broadway shows. It's new-ish and very clean. Otherwise, it's an actual nightmare to have to traverse Times Square every time you leave the hotel.
Residence Inn Midtown East is perfect if traveling with kids because the rooms are huge by NYC standards and also a good location. Very typical Residence Inn accommodations, nothing special.
Renaissance Midtown has the most comfortable hotel beds I've slept on in years. Recently renovated. Rooms are lovely and the service is great.