Visiting in March, never been to the area...appreciate any help on a nice upscale hotel or suite in midtown or lower Manhattan.

How upscale do you want to go?  On your dime, or the company's?
The Regency on Park Ave and 60th is one of the preferred spots for LA music/film execs.  The W on Lexington Ave.  Four Seasons on 58th Street/off Park.  The Plaza, maybe.  For dirt cheap, The Wellington on Broadway and 55th.  But it's touristy, not upscale.