Definitely leave it to air as long as you can, more for the smell than anything, although I don’t remember it being too bad at all 
Good choice with Otty, I spent ages comparing before I went with it, and it still super comfy a couple years on 
@anon28680395 I’d say it’s more preference rather than a benefit over the others. They’re all variations on a theme and I liked the hybrid mix of Otty as opposed to a full on memory foam one, plus I got 2 pillows in a deal so think financially it was the best for me at the time as well. But that’s just me!