Upon opening, the mattress inflates itself rather quickly. As far as comfort, this is definitely a medium hybrid mattress. The mattress has some give underneath your rear and is soft overall, so if you prefer a very firm mattress this is not for you. I highly suggest going to a local mattress store to lay on a few hybrids (medium vs firm) to get a feel for what you like before doing any online mattress shopping. So far it has held up well.