There is no lounge at the hilton ORD. they will give you a breakfast coupon (good for the continental breakfast, full breakfast $3.00 more)

The restaraunt and bar have really good food. Ate there multiple times.

One place to consider if your Plat SPG, is the Westin Ohare (no club there either) but the Benchmark (restaraunt there) has some outstanding food as well.

However if its a really early morning flight, staying at the hilton ord will shave 15-20 minutes off your morning (just walk to the terminal vs shuttle)

Also the Marriott Renanissance is an outstanding property (and has a lounge). The "R" bar there is great the restaraunt also has good food.

I'd skip the Marriott Ohare (its just dated)