It's way too long for any of the lounges and if you use the PP sleeper rooms it will work out more expensive than a hotel. At that time there is also no point in going into town.
I have stayed at several of the airport hotels and like the Four Points the best. You can book a rate that includes r/t airport transfer and breakfast that is competitive with the others. If you want to save a little bit of money you could go for the Red Fox or Ibis. A step down but still good.