The Omni has the worst mattresses I've ever slept on! They were so soft that when I arrived I called down to the front desk and asked to view another room. They were all the same. I had them bring a board to put under the mattress and the service person acknowledged how bad the mattresses were. Really inexcusable!
In addition, they didn't have conditioner in the shower (a standard item at most hotels). The rooms were dingy and bathrooms in need of updating. I would never stay there again given the much better choices that New Haven has to offer - especially if you are visiting Yale.