One of my friends is an FA for AA and doesn't like the enclosed 1st class seats - says they feel like a coffin
I doubt I would pay to upgrade for a full bed. Except for my last trip when I kept opening my mouth when I was sleeping and waking up with dry mouth, I've been happy in Delta's Business Elite seats that fold all the way down flat.
Flying to London as a kid my Dad got each of us a row of seats in coach. They were cheaper and lot more comfortable because we could completely lie down flat - you couldn't do that in 1st yet. But I've heard now that even though you pay for the seat, unless there's a butt in it, they reserve the right to take the extra seats from you, refund you the $$$ and stick some smelly people next to you