i just planned an event about a month ago. dinner was for ~25-30 people and was held in one of the private rooms in the mezz area. I thought it was a great event - food was excellent, service was excellent. I have never been there before, so its tough to compare for me. Only issue was that some of our guests (from the midwest) didn't get enough to eat (good thing shake shack is across the street). It was pricey however - but i thought the did a good job.
I attended a private party at EMP but had nothing to do with organizing it. Since it was a year and a half ago I don't remember specifics (except the exquisite bday cake), but my overall impression was that everything about the evening was perfection. Never having eaten at the restaurant before, I don't know if the food is up to the same level (and it was a different chef besides) but everything was delicious, professionally and beautifully served, and the party was a total success.