I bought a King Coil mattress from Sleepy's. They told me it was such a good brand.
After sleeping on it for one night it is hard to get out of it in the morning because it is sunk in so far. Turned it around the next day and the same thing happened. This is no doubt the worst mattress I have ever purchased. I have a 10 year old Serta that I paid a lot less for and it doesn't sink in.
Do not buy a King Coil mattress and don't shop at Sleepy's. They are a rip off.